“The single most important thing we want to achieve is for President Obama to be a one-term president,” Mitch McConnell said days before the 2010 election.

Those words have become the guiding light for Congressional Republicans, and explain nearly every decision the GOP has made since the last election. The better the economy performs, the more likely it is that Obama will be re-elected. The longer the recession lasts, the better the chance that McConnell will get his wish.

This dynamic illustrates why Republicans are opposing policies they once supported in Obama’s new jobs plan, such as a payroll tax cut and infrastructure spending. As one senior GOP Republican staffer told Politico, Republicans “don’t want to co-own the economy.”

It also illuminates why Republicans are taking the unusual step of publicly going after the Federal Reserve today, urging Ben Bernanke not to take further action to stimulate the economy. With Congress eternally deadlocked because of Republican obstructionism, the Fed is perhaps the only institution that can still give the economy a boost.

The Fed, of course, is supposed to be politically independent and should pursue policies that are in the best interest of the American economy regardless of political pressure. But if those policies happen to improve the economy, which in turn improves Obama’s political standing, then Republicans will predictably resort to their default strategy: just say no.