In the end, it wasn’t the Appalachian Trail that brought down Mark Sanford. It was President Donald Trump. 
 
 The South Carolina congressman’s stunning defeat in Tuesday’s Republican primary effectively ended the turbulent two-decade career of a political icon who once harbored presidential aspirations. State Rep. Katie Arrington defeated Sanford 50.6 percent to 46.5 percent. 
 
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 From his time as a congressman in the 1990s, to his eight-year governorship, to his unexpected House comeback that followed, Sanford had long established himself as a figure who cut against the grain — the rare politician who loved to break with his own party. Yet in taking on Trump, his friends and political allies say, he took it a step too far. 
 
 His defeat is bound to raise fears among Republicans about the political perils of crossing a president who remains deeply popular with GOP voters. In recent days, Sanford himself had expressed concern that a loss in the primary would discourage what dwindling GOP dissent against the White House remains. 
 
 At the heart of Sanford’s downfall was a fundamental miscalculation, those close to him said: that he could go after the Republican president — vigorously, and sometimes in deeply personal ways — and get away with it. 
 
 “Mark had a long and storied career, he was a very famous and successful politician. But he didn’t read the tea leaves right, and that came back to haunt him,” said former state Rep. Chip Limehouse, who hails from a prominent Charleston family and has known Sanford for years. “Mark misjudged it, attacking Trump. That’s what killed him.” 
 
 The South Carolina Republican, 58, was nothing if not durable. After entering office in the 1994 Republican revolution, Sanford weathered a series of political storms. 
 
 As a congressman in 1999, he and then-Oklahoma Rep. Tom Coburn staged a bold public protest against their own Republican leaders by shutting down floor debate on an appropriations bill. As governor, he repeatedly collided with GOP members of the state Legislature — at one time, bringing a pair of pigs to the House chamber to protest deficit spending in the state budget. When it was revealed in 2009 that he’d had an affair with an Argentine woman, while he had claimed to be hiking the Appalachian Trail, he ignored GOP calls for him to step down. 
 
 And after the National Republican Congressional Committee cut off support for his 2013 congressional campaign, he plowed ahead and defeated his Democratic opponent. 
 
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 In each case, Sanford found a way to hang on. Yet as the 2018 campaign kicked into high gear, Sanford, who’d never lost a political race, found himself under mounting pressure. 
 
 At issue: His relentless criticism of the president. 
 
 Arrington, Sanford’s rival, cast the congressman as a disloyal Never Trumper. She aired commercials highlighting cable news clips spotlighting negative comments that he’d made, including one instance in which he said Trump should “just shut up” and stop spending so much time paying attention to critics. Arrington portrayed the incumbent as an obstructionist who was hell-bent on getting in the president’s way. 
 
 “He made a calculation in the post-Trump election that he was going to stand on principle. … But there’s an expectation out there, at least in South Carolina’s 1st District, that you have to show deference to the president,” said Scott English, a former Sanford chief of staff who remains close with the congressman. “In this race, the ideas didn’t matter nearly as much as whether he’d been sufficiently loyal to the president in the eyes of voters.” 
 
 Trump himself stayed out of the race until just hours before the polls closed on Tuesday, when he sent out a surprise tweet calling for the congressman’s defeat. Arrington’s campaign rushed out a robocall to 50,000 homes highlighting the president’s last-minute endorsement. 
 
 Other South Carolina pols say that while Sanford’s opposition to Trump was his undoing, other factors were at play. Some people close to the congressman believe that voters never really got over his affair, which destroyed his national ambitions. Others say there was general exhaustion with a politician who’s been around since the mid-1990s and that voters were ready for someone new like Arrington, a political newcomer serving her first term in the state Legislature. 
 
 In what was perhaps an early sign that his political strength was abating, Sanford received just 55 percent of the vote in his 2016 primary, against an opponent who spent little. 
 
 Others say Sanford simply failed to run an effective race this year, allowing himself to be outworked. Sanford’s lethargic reelection bid was a lightly staffed shoestring affair. Many of the advisers who guided his gubernatorial and congressional campaigns were not involved. 
 
 After realizing he was in trouble, the ever-frugal congressman, who hadn’t spent money on TV ads in five years, rushed out a slate of commercials. Some went after Arrington directly. Others tried to make the case that Sanford had cooperated with the White House. 
 
 While Arrington relentlessly cast Sanford as anti-Trump, his backers worried, Sanford struggled to find a coherent message. 
 
 “She got up on TV early and defined the message, and he let her define him,” said state Rep. Nancy Mace, a Sanford supporter. 
 
 In the days leading up to the primary, Sanford was hesitant about his prospects. During an interview with POLITICO on Saturday evening in Mount Pleasant, he repeatedly refused to assess his prospects. And when a constituent approached him to ask what polls showed, he paused. 
 
 “They show different things,” he said. 
 
 Behind the scenes, Sanford’s allies worried that he had a ceiling of support — and that by going after his disloyalty to the president, Arrington had found a way to surpass the battle-hardened incumbent. 
 
 His political career appears to be over. 
 
 “I don’t see any future for him from here [in politics]. This is basically it,” said English, who added that Sanford could still engage in conservative causes from outside elected office. “This is the last ride of Mark Sanford. It’s been a fascinating ride.” ||||| Exceeding all expectations, the former governor and Appalachian-trail hiker regained his old Congressional seat, whipping Elizabeth Colbert Busch by nine points. 
 
 RANDALL HILL / REUTERS Former South Carolina Governor Mark Sanford celebrates his victory in the South Carolina first district congressional race at Liberty Tap Room in Mount Pleasant, S.C., on May 7, 2013. 
 
 Now Mark Sanford will be the one who has to forgive. Exceeding all expectations, the former governor and Appalachian-trail hiker regained his old Congressional seat, whipping Democrat Elizabeth Colbert Busch by nine points in a May 7 special election. 
 
 His victory seemed so unlikely three weeks ago — when a report emerged that his ex-wife Jenny had filed a complaint that he violated their divorce agreement by showing up at her house without permission — that the National Republican Congressional Committee pulled its cash from his race. Local Republicans fled whenever reporters asked if they supported him. 
 
 Sanford was easy to underestimate. Political comebacks following flamboyant extramarital affairs are rare; he took out an ad in the newspaper comparing his campaign to the Alamo in ways that didn’t make sense. His few boosters didn’t help much: Cheating website AshleyMadison.com put his face on a billboard; Larry Flynt donated $2,600 to Sanford “because no one has done more to expose the sexual hypocrisy of traditional values in America today.” “I’m outnumbered right now,” he said in his Alamo ad, “but will fight to the end toward freedom and financial sanity in Washington so important to sustaining it.” But Sanford overcame it all, partly just by working harder. On the last day of the campaign, Sanford made ten stops; Colbert Busch didn’t make any. 
 
 Sure, having Sanford in the House is another target in the Democrats’ accusations of a war on women. Still, it was dumb of the GOP to abandon Sanford because South Carolina’s first district is way red and Sanford dominated the primary. 
 
 Sanford says he’s learned a lot about forgiveness and accepting other’s selfish choices. “After you’ve been through a complete cratering in life, you learn to let it go,” he said. The GOP better hope so, because he’s going to be around for a while. 
 
 This article has been updated ||||| National Republicans are pulling the plug on Mark Sanford’s suddenly besieged congressional campaign, POLITICO has learned — a potentially fatal blow to the former South Carolina governor’s dramatic comeback bid. 
 
 Blindsided by news that Sanford’s ex-wife has accused him of trespassing and concluding he has no plausible path to victory, the National Republican Congressional Committee has decided not to spend more money on Sanford’s behalf ahead of the May 7 special election. 
 
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 reset POLITICO Roundtable: Sanford in trouble Sanford: I didn't properly love my wife TOP 5 ways to apologize 
 
 “Mark Sanford has proven he knows what it takes to win elections. At this time, the NRCC will not be engaged in this special election,” said Andrea Bozek, an NRCC spokeswoman. 
 
 (PHOTOS: Mark Sanford’s career) 
 
 Sanford is facing Democrat Elizabeth Colbert Busch, a Clemson University administrator and sister of comedian Stephen Colbert, in a race that has grabbed the national spotlight. 
 
 The NRCC’s move comes hours after Tuesday night’s report by the Associated Press that Sanford’s ex-wife, Jenny Sanford, filed a court complaint accusing him of trespassing at her home in early February – which would be a violation of the terms of their divorce agreement. 
 
 Republicans said they were caught off guard by news of Jenny Sanford’s complaint. They worry other damaging revelations about Mark Sanford’s personal life that they aren’t aware of could come out in the coming weeks. 
 
 The NRCC has spent a nominal amount on the race on polling and other activities. But officials determined that devoting potentially millions more — which was under discussion — isn’t worth it. 
 
 “This is an unfortunate situation but this is what happens when candidates aren’t honest and withhold information,” said one GOP operative. 
 
 (Also on POLITICO: Ex-wife claims Sanford trespassed) 
 
 Sanford’s campaign did not respond to a request for comment. 
 
 Sanford’s political career was derailed four years ago after he admitted having an affair with an Argentine woman, and now he is seeking the House seat he held for three terms in the late 1990s. The district heavily favors Republicans, so a win by Colbert Busch would be a major upset. 
 
 The former governor’s personal life has taken center stage in the race. Sanford, who spent eight years as governor and six years in Congress and for a time had been seen as a serious potential presidential candidate, has crisscrossed the Charleston-area district apologizing to voters and casting himself as a figure of repentance and redemption. 
 
 (Also on POLITICO: Sanford: I entered Jenny's home to watch football) 
 
 The NRCC’s decision came as national Democrats began pouring money into the race. On Tuesday, House Majority PAC, a Democratic outside group, started running a TV hammering Sanford for spending taxpayer money to fund his trips to Argentina (The former governor later reimbursed the state for the trips). An official with the group said it was spending in the mid six-figures to run the ad. 
 
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– Rep. Mark Sanford can now spend as much time as he wants hiking the Appalachian Trail: The congressman and South Carolina governor lost his Republican primary Tuesday, hours after a very critical tweet from President Trump, Politico reports. "Mark Sanford has been very unhelpful to me in my campaign to MAGA. He is MIA and nothing but trouble. He is better off in Argentina," Trump said, referring to Sanford's infamous 2009 affair. "I fully endorse Katie Arrington for Congress in SC, a state I love," Trump said. Analysts say the 58-year-old Sanford, whose political career is now probably over, criticized President Trump more often than South Carolina voters considered acceptable. "We are the party of President Donald J. Trump," Arrington told supporters after winning just over half the vote. Sanford, who has long seen himself as a political outsider, was unrepentant after the defeat Tuesday, which was his first-ever election loss, CBS reports. "I stand by every one of those decisions to disagree with the president," said the Republican, who was re-elected to his old House seat in 2013 despite the national GOP withdrawing support. In other races, Nevada's Sen. Dean Heller cruised to victory in the GOP primary, the Washington Post reports. He had been expected to face a tough challenge from activist Danny Tarkanian, but Trump persuaded Tarkanian to seek a congressional nomination instead, which he won Tuesday. In North Dakota, Rep. Kevin Cramer won the GOP primary for a Senate race. He will face Democratic Sen. Heidi Heitkamp this fall in a race that could determine control of the chamber.