On a party-line vote, the Senate Judiciary Committee has approved the nomination of Goodwin Liu for the Ninth Circuit. Because of the timing, many are looking at the impending Liu floor fight as a harbinger of the political fight over Elena Kagan for the Supreme Court. Indeed, Committee Republicans used the Liu nomination to test-drive what appears to be an emerging meme for Kagan opponents:

Republicans used the hearing to attack both Liu and Obama Supreme Court nominee Elena Kagan, as ranking Republican Jeff Sessions (R-Ala.) criticized both Liu’s lack of previous judicial experience as well as Kagan’s.

But leaving aside the memes and the horse race, there is another reason that the Liu and Kagan nominations should be viewed as similar in an important way — both are examples of the importance of allowing both sides into the argument. Liu is controversial because he is a strong progressive voice, young, and with a compelling back-story that makes him seem destined for the Supreme Court. But contrary to the meme, this is exactly what should make him a good candidate. Good law does not result from group-think, and strong and passionate voices debating in good faith should be welcomed form both sides. After eight years of a Republican President, there is surely both a need and room for strong progressive voices in the courts. While the Ninth Circuit alone already has progressives very well represented by the likes of Judge Kozinski, the Ninth Circuit does not exist in isolation, and the addition of another smart progressive contributes to the broader national legal discourse.

And that extends to the Supreme Court as well. In fact, many progressives (and at least a few moderates) were strongly hoping that Seventh Circuit Judge Diane Wood would be nominated to replace the retiring Justice Stevens. Wood, who has sparred with Judge Richard Posner on the Seventh Circuit and more than held her ground, was thought to have been the perfect candidate to replace the “liberal lion” that Justice Stevens became for the Court. And she would have been the perfectly matched new sparring partner for Justice Scalia. It could have been reminiscent of the fictional debates between co-appointed conservative and liberal Justices in NBC’s The West Wing.

But Kagan succeeds in sending the same message in another way. As Dean of Harvard Law School, Kagan was controversial among some more purist progressives for having been involved in the hiring of a few high-profile conservative law professors. The fact that this is grounds for controversy is an unfortunate commentary on the state of ideological diversity in higher education, but it is an excellent sign of what might make Kagan a great Supreme Court Justice — a willingness to listen to the other side and even, on occasion, be persuaded to find some common ground. Given that Kagan will almost certainly be a reliable progressive vote on most core issues for progressives (e.g. abortion rights) and given that Kagan is replacing the consistently progressive Stevens, there is no serious cost to progressive policy priorities to embracing her more collegial ideological style. Progressive critics like Glenn Greenwald are, frankly, fighting the wrong battle by viewing her open-mindedness as a vice.

And those conservatives who seem bent on opposing Kagan and Liu at all costs are just missing the point entirely.