Some big news on the judicial confirmations front: Democrats will bring the nomination of Berkeley Law Professor Goodwin Liu to the floor, after months of stalling in the face of a determined campaign by conservatives to block him:

Liu, a professor and associate dean at the University of California-Berkley school of law, failed to receive Senate approval in the last Congress and faces a tough formal road through a more closely divided Senate this time around. Some Republicans have criticized Liu for what they say is his support for an activist approach to the law and for writing judgments in favor of more socially liberal positions like same-sex marriage.

Here’s why this is so important: Liu’s confirmation battle is a symptom of a much larger problem — the GOP’s success in blocking Obama’s judicial nominations. There are 110 vacancies on the federal bench, a vacuum that leaves the judiciary ideologically skewed to the right.

The lack of Democratic appointees has allowed a more conservative federal bench to interpret the law in ways that drastically affect Americans’ daily lives. Only 133 of Obama’s nominees have been confirmed, far fewer than George W. Bush or even Bill Clinton. The administration itself has also failed to put forth enough nominees, and hasn’t fought very hard for those they have.

Despite their claims, social liberalism isn’t the big reason Republicans oppose his nomination. Liu is recognized by conservatives as uniquely bright, to the point of winning plaudits from conservative attorneys like torture memo author John Yoo and former Solicitor General Kenneth Starr.

The real reason Republicans are trying to block Liu is this: Because of his youth (he’s 39), intelligence and outlook, he’d be a tempting choice the next time a spot opens up on the Supreme Court. A Liu pick would delight Obama’s liberal base and — depending on who he replaced — potentially move a conservative dominated, corporate friendly court to the left for the first time in generations.

But Liu has to make it to the federal bench first. Republicans know that. And that’s why Republicans have rallied to block his nomination. As frustrating as it might be, they’re acting entirely rationally in doing so. Dems, after all, have done thehe same: In 2002, Senate Democrats filibustered the nomination of conservative attorney Miguel Estrada, fearing that his next stop would be the Supreme Court. In the absence of some kind of deal, Republicans are likely to succeed in doing the same thing.