This week’s Republican sweep of gubernatorial races in Virginia and New Jersey was more than a defeat for Democrats. It was also the latest blow for the Obama administration’s increasingly imperiled health care legislation as it comes up for a possible vote this Saturday.

While President Obama has touted health care reform as the signature piece of his domestic policy agenda, voters in both of the high-profile races disagreed on the issue’s importance. In New Jersey, health care ranked fourth on the list of voters’ concerns. Just 17 percent of Garden State voters considered health care the primary issue. The economy (32 percent), property taxes (26 percent), and corruption (20 percent) all rated as more important. Health care ranked higher in Virginia, at 24 percent. But that still made it a distant second to the dominant campaign issue, the economy, which was most important for 47 percent of voters. Notwithstanding President Obama’s defiant pledge this September that he would “not accept the status quo as the solution,” Tuesday’s elections made clear that, for many voters, there are more pressing problems to be addressed.

The election results also suggest that there is scant appetite for a costly new legislative venture. Indeed, Republicans in Virginia and New Jersey were successful in large part because they campaigned as staunch fiscal conservatives. Virginia Governor-elect Bob McDonnell ran on a platform of limited government, low taxes, and opposition to surging federal spending. Chris Christie enjoyed similar success exploiting incumbent governor Jon Corzine’s failure to curb spending and taxes in New Jersey. This backlash against big spenders can hardly be encouraging for the Obama administration and its Democratic allies as they seek to ram through a health care reform bill that the bipartisan Congressional Budget Office has pegged to exceed $1 trillion in new federal expenditures – let alone the $2.4 trillion that Republicans on the Senate Committee estimate as the ten-year cost of the House health care bill.

Equally damaging for Obamacare’s prospects is the disaffection of independents. In both New Jersey and Virginia, independents broke overwhelmingly for the Republican candidate. Chris Christie won 58 percent of New Jersey’s independent voters, to Corzine’s 31 percent. The results in Virginia, the archetypal swing state, were even more telling. On an election day when one third of voters identified as independents, the Republican was preferred by a 2-1 margin. More than a momentous political shift – independents were mostly split between the two parties during the 2008 presidential elections – it is also a warning to moderate Blue Dog Democrats in Congress: Toe the Left’s legislative line, and lose your seat in 2010.

The message has not gone unnoticed by the Blue Dogs. In the wake of Tuesday’s defeats, nervous Democrats from conservative and swing states were urging restraint on heath care reform. Rep. Parker Griffith, a freshman Democrat from Alabama, told Politico that he was “very, very sensitive” to the fact that the agenda of the Democratic Congressional leadership has “the potential to cost some of our front-line members their seats.” Such concerns can only complicate Nancy Pelosi’s efforts to recruit Blue Dog Democrats to support a health care bill that would inflate the deficit and radically expand the scope of government. Already, some 30 Blue Dogs are considering voting “no” if the health care bill comes up for a vote this weekend.

Obamacare is not dead and buried, however. Given the Democrats’ current majority, some version of the bill still could pass before the end of the year. And it does not hurt the Democrats’ cause that health care lends itself to unscrupulous politicking. This too was one of the lessons of this week’s elections, as Democrats maintained an advantage on health care even as they lost. In New Jersey, Corzine deployed a version of President Obama’s health care battle plan, decrying his Republican rival Christie as a pawn of “big insurance companies” who would slash services to boost the insurance industry’s profits. One Corzine campaign ad even suggested that Christie would deny New Jersey women coverage for mammograms. Christie responded with an effective counter-ad that mentioned his mother, a breast cancer survivor, but Corzine won the fight: Among voters who named health care their main issue, Corzine took 78 percent to Christie’s 19 percent.

That was not because Corzine made the better argument. In fact, Corzine’s attacks on insurance companies were misdirected. As Merrill Matthews of the Council for American Health insurance observed the Wall Street Journal, one of the main reasons that New Jersey has some of the highest health insurance premiums is the large number of state mandates requiring insurance companies to provide certain kinds of coverage. That in turn drives up costs and denies consumers the freedom to choose their own policies. Corzine’s success in deflecting blame from the government to the private sector serves as a reminder of how easy it can be to demagogue the health care issue.

Even so, the Republican revival evidenced by this week’s elections marks a real setback for Democrats. They have staked their success in 2010 on their ability to push through Obama’s legislative agenda, most notably health care reform. But two months before it arrives, 2010 is shaping up to be a bad year.