Republicans have already helped to sink a few key administration nominees. The House Republicans cast a unanimous vote against the stimulus package. They are likely to repeat that trick when they have to vote on the bill that comes out of the reconciliation process.
As a result, Obama now looks far too defensive for a president still in his first 100 days of office. By denying it serious bipartisan cover, the GOP has succeeded in tying him to the unpopular stimulus bill. If it fails, Republicans will argue that he has failed. The charge will resonate.
That's a remarkable oppositional achievement so soon into a popular president's first term, and it's only a start. Many Republicans are still professing their willingness to "work with" Obama. However, they'll be just as happy to work against him on issues ranging from taxes to spending to health care to labor law.
The sense, from watching Republicans these past few weeks, is that they are finding being in the opposition liberating. Without a governing coalition to hold together, they don't have to back bad legislation. Without Bush to hold them back, they can soar.
Indeed, one of the only advantages of the political duopoly is that on occasion it encourages one party to do something decent it would otherwise not be so inclined to do, merely for the appearance of product differentiation. (As in the only overseas intervention that Obama didn't seem to like being the one in Iraq that he could blame on his political opponents.) GOP opposition to the advancing state may be too little, too late. But it deserves a half a hat tip, at least.