Health Law Rollout Provides Rich Target for Oversight Chief WASHINGTON - Representative Darrell Issa has long been known on Capitol Hill as one of the most aggressive - some would say overzealous - thorns in the side of Obama administration, using his seat as chairman of the House oversight committee to trumpet any missteps that can be traced to the White House. But with the troubled rollout of the health care law, the administration has offered Mr. Issa his richest target yet. And he is running with it. "This was President Obama's signature legislative achievement," Mr. Issa, Republican of California, said in a statement announcing his latest hearing on the topic, scheduled for Wednesday before the House Committee on Oversight and Government Reform, which will feature four administration officials. His administration had hundreds of millions of dollars and total control to complete the project. But the investigation, even at this early stage, has turned into a nasty public relations war that will be on full display at Wednesday's hearing, where Todd Park, the administration's chief technology officer, will testify under subpoena. The subpoena demand by Mr. Issa has evoked protests from the White House - and many in the technology field - who argued that Mr. Park should be left to do his work fixing the problem-plagued HealthCare.gov website. Republicans are hardly deterred, passing out a "House Republican Playbook" last week that provides "messaging tools to help you communicate in your district about the disastrous Obamacare rollout" - including sample Twitter messages, Facebook postings and op-ed articles. Its title: "Because of Obamacare ... I Lost My Insurance. White House officials are distributing their own 25-page guide titled "G.O.P. Obstruction/Sabotage - Affordable Care Act," detailing three years" worth of efforts by Republicans to kill the law, with new entries suggesting that the latest round of House investigations is a political stunt. The barrage of claims and counterclaims that has emerged - as Mr. Issa and others selectively leak an array of investigation documents, including those that discuss allegations that the health care site might be vulnerable to cyberattacks - has some experts worried that the investigations themselves could cause lasting damage to the health care effort, even once the insurance exchange is fixed. "I think it's a serious threat to the viability of reform," said Daniel N. Mendelson, a former health policy adviser to President Bill Clinton who is now chief executive of Avalere Health, a research and consulting firm. They will succeed with depressing enrollment if they keep up with these aggressive tactics. There is evidence that the Republican effort is already paying off. Some Senate Democrats are joining in the Republicans" call for a comprehensive investigation, while others, nervous about their re-election prospects, are breaking with the White House to propose legislative fixes to the Affordable Care Act, such as delaying tax penalties for people who go without insurance in 2014. But other Democrats on Capitol Hill say that while there are serious questions that need to be answered, they believe Republicans, including Mr. Issa and Representative David Camp of Michigan, the chairman of the Ways and Means Committee, are being driven more by a political agenda than any real desire to figure out what went wrong. "It is outrageous and destructive, and it has further poisoned the atmosphere up here," Representative Sander M. Levin, Democrat of Michigan, said of the decision by Mr. Camp to also subpoena documents as part of the inquiry. This continues to be a search for what will essentially help Republicans in the November 2014 election, instead of trying to make things work before that. Mr. Issa declined a request for an interview, but Mr. Camp said Tuesday that his investigation was in the public interest. "The questions aren't being raised just by me," Mr. Camp said. This is trying to get answers on behalf of millions of Americans. To critics of Mr. Issa, the investigation into the health law rollout follows a pattern he established in his earlier inquiries, such as the investigation into the deadly attack last year on the United States mission in Benghazi, or the inquiry into a failed Justice Department program known as Operation Fast and Furious that was intended to curb illegal gun flows along the Mexican border. "He comes up with inflammatory accusations, the type of accusations that automatically make headlines," said Representative Elijah E. Cummings of Maryland, the ranking Democrat on the committee. Then he goes out and searches for facts that he cannot find. Mr. Cummings and White House officials both pointed to at least two assertions that Mr. Issa has made related to the health care program that they say are entirely false or distortions. These include the claim that the HealthCare.gov website, as of late September, could handle only about 1,100 users simultaneously, or the assertion that the White House might have intentionally disabled the site's so-called anonymous shopper function so that people enrolling could not see how much the insurance would actually cost. A spokesman for Mr. Issa defended the comments, saying that Mr. Issa's remarks had been based on information he had gathered in the early stages of the investigation, and instead accused the Obama administration of withholding documents that would allow Mr. Issa to answer questions. "We are following the facts, and pressing the administration to reveal them," Frederick Hill, Mr. Issa's spokesman, said. What has most angered the White House so far is the demand by Mr. Issa that Mr. Park, a little-known bureaucrat, testify Wednesday before his committee. Mr. Park has never been in the spotlight before, and preparing for this appearance - in addition to the hearing itself - will probably distract him from several days of work, which the White House deems critical as the deadline that Mr. Obama has set for a fix approaches. Mr. Park had little to do with the development of HealthCare.gov, but he has been working furiously - even sleeping on the floor of his office, officials say - to try to fix it. Three technology experts who met during stints in the Obama White House even set up a website called Let Todd Work, saying that his previous efforts on behalf of the federal government had helped save millions of dollars and that he should be left out of the political spectacle now playing out on Capitol Hill. Late Tuesday, the White House said Mr. Park would appear before Mr. Issa's committee on Wednesday, as ordered, though a spokesman for Mr. Park's office, Rick Weiss, called the subpoena "an unfortunate and unnecessary step." There will be competition for viewers who want to follow the interrogation, though. It will be one of two House hearings focused on health care that will be broadcast live on Wednesday morning, the second sponsored by the Homeland Security Committee and focused on security threats to the website.