It’s official: President Obama will choose Chief of Staff Jacob Lew as his choice for Treasury Secretary, replacing Timothy Geithner. As with Chuck Hagel and Defense, there’s no mystery to Obama’s decision to choose Lew. The next year will be consumed with budget issues, and as former head of the Office of Management and Budget under Bill Clinton and Obama, Lew is well equipped to deal with them.

Despite Lew’s long experience in government, Senate Republicans are already voicing their disappointment with the pick. Politico notes that Lew has “irked” Mitch McConnell and GOP members of the Senate Budget committee. “We’ve got to have a person who has credibility with the leaders of the American and world economy, someone who has credibility with the Congress, and I would feel like Mr. Lew’s nomination would be a mistake,” says Alabama Senator Jeff Sessions, the top Republican on the committee.

Historically, the Senate has given the White House wide leeway in how it staffs its administration. Barring extraordinary circumstances, cabinet nominations are almost always confirmed, as they should be — the chamber’s role is to give advice and consent, not set policy for the administration. But if the mounting opposition to Lew — and current opposition to Hagel — is any indication, Republicans are prepared to jettison that norm so that they can block Obama’s ability to pursue his agenda.

It’s hard to overstate how ridiculous this is. Remember, Republicans lost the 2012 elections. Not only did Mitt Romney lose the presidential election by nearly four points, but almost every competitive Senate race broke toward the Democrats. Even if you don’t think this constitutes a mandate for Democratic policies, it’s clear that it is an endorsement of Democratic leadership. And as such, Republicans should swallow their pride and allow Obama to staff his administration, as is a president’s prerogative.

If the GOP wants to pick cabinet members, then it should start by winning a presidential election.

Jamelle Bouie is a staff writer at The American Prospect, where he writes a blog.