Republican presidential field still lacks a unifier The road to the Republican presidential nomination just got longer, steeper and less predictable. Mitt Romney is still the prohibitive front-runner as the race heads now to Arizona and Michigan. He alone has the financial and organizational wherewithal to stay in the race and fight in every contest through the last big day of balloting, on June 5. But by losing three out of three Tuesday contests to Rick Santorum - two of them in blowouts - Romney underlined several of the weaknesses of his candidacy, starting with his failure to connect with the GOP's most conservative voters. In Minnesota, Colorado and Missouri, Romney lost ground to Santorum in those areas where the Republican base is strongest. He also lagged far behind his own performance four years ago - receiving in Minnesota, for instance, less than a third of the votes he won in 2008. That suggests a general lack of enthusiasm for his candidacy and, perhaps, a specific aversion to the former Massachusetts governor - echoing recent polls that have shown Romney getting less popular as the race continues. Nothing changed in terms of the delegate count, as strategists for the front-runner were quick to note. The caucuses in Minnesota and Colorado were just the start of their election processes, and Missouri's primary was a so-called beauty contest, with no bearing on how delegates are awarded. Romney is still comfortably ahead in the very early count. But if Tuesday's results merely delayed the inevitable, as many party analysts and insiders suggested, it is a delay that will be costly for Romney in terms of time, money and the difficulty of waging two fights at once, against President Obama and a persistent pack of GOP rivals. Romney has shown a pattern throughout the campaign of ignoring his Republican opponents when doing well, only to suddenly engage them when he stumbles. So it was no surprise that he held an airport news conference Wednesday in Atlanta to assail Santorum and offer, strategists said, a preview of what is to come. Having let up on Gingrich only to watch his campaign revive in South Carolina after poor showings in Iowa and New Hampshire, the Romney team said it would try to yoke both him and Santorum to the hated Beltway establishment. "Rick Santorum was a major earmarker and continued to defend earmarks," Romney said in Atlanta, referring to the congressional practice of designating federal money for specific local purposes. Republicans spent too much money, borrowed too much money, earmarked too much, and Rick Santorum and Newt Gingrich have to be held accountable. Santorum, who seemed to fade after barely winning Iowa, offered a tart taste Wednesday of what Romney could expect in return. Appearing early Wednesday on CNN, the former Pennsylvania senator pushed back against Romney's election night assertion that the Republican presidential contest amounts to a choice between a business-world outsider and a Washington insider. "Mr. Outsider was for a government takeover of healthcare, was for a government takeover of the private sector - the Wall Street bailout - and for a takeover of industry and energy with cap and trade," Santorum said. So, Mr. Private Sector was Mr. Big Government. If Tuesday's balloting produced an embarrassment for Romney, it was a complete humiliation for the former House speaker. Gingrich finished a distant third in Colorado and fourth in Minnesota, and did not even appear on the ballot in Missouri, having failed to qualify. Apparently sensing disaster, he spent election day in Ohio, which does not vote for another month. Given his dismal performance, it has become much harder for Gingrich to argue that he is the conservative alternative to Romney, a case he has pressed since his lone victory last month in the South Carolina primary. It would be foolhardy, however, to predict Gingrich's demise, given his earlier recoveries from political near-death. Gingrich's best hope appears to be a strong performance in the next debate, in just under two weeks in Arizona, and a batch of wins when the campaign heads south next month to Georgia, his home state when he was in Congress, Tennessee and Oklahoma. Like Gingrich, Santorum is picking and choosing his fights. He signaled Wednesday that he would make his next stand in Michigan, which holds its primary the same day as Arizona, on Feb. 28. It is a risky move: Romney, whose father was a popular three-term governor of Michigan, was born in Detroit and remains something of a favorite son. But the state has an open primary, meaning Santorum can target his more economic populist message at working-class voters, regardless of their political affiliation. And unlike Arizona, which is a winner-take-all contest, Michigan allows even nonwinners to collect delegates. To pose a true threat to Romney, however, Santorum must do more than win small caucus states, which favor the candidate with the most ideologically motivated supporters, or low-turnout primaries like Missouri. A win in Michigan would be a start. But he must build a national organization and fundraising base quickly, because Super Tuesday - when 11 states vote - is less than a month away. As for the final candidate in the race,Rep. Ron Paulof Texas, he has yet to win a state, and after disappointing finishes in the Iowa and Nevada caucuses, seems less of a factor with each passing contest. Maine gives him a shot at getting back into the competition with its caucus on Saturday. For all his difficulties, Romney still has much going for him. Apart from his huge fundraising advantage, he has allies willing to spend handsomely - nearly $20 million so far - on TV advertising. He has shown the ability, through strategic adjustment, financial firepower and sheer tenacity, to fight and win when he absolutely must. The month of March, when the contests resume in a rush and delegates start quickly piling up, will offer an important test. "If we're correct about Romney's intrinsic advantage, which is a good organization and a lot of money, then it's going to pay off," said Rich Galen, a veteran GOP strategist watching the nomination contest from the sidelines. If we're wrong about it, then he's not going to be the nominee. Michael Finnegan in Atlanta and Paul West in the Washington bureau contributed to this report.