I think there are in fact plenty of defenses of the film—even paeans to it—written from the "liberal" perspective Tony offers, including his own review and one by historian Louis Masur (no relation). In some sense, though, the category "liberal" is confusing here because it seems to me that Brooks and Douthat praise the movie for reasons that aren't so different from Tony's. If I were going to take this further, I would suggest that much of the critical acclaim the film has received is written in an implicitly liberal vein—although critics are generally more reluctant than political columnists to interpret the film in explicitly political or prescriptive terms. Meanwhile, Greg Sargent (who identifies himself as a liberal) and others have insisted that Lincoln is not a movie that extols compromise but, rather, one that shows Lincoln standing firm in his principles and pushing and cajoling others to come around.
As a historian, I think Sargent is more right than Brooks. The compromises that Lincoln did not make are more significant than the ones he did. At the same time, however, the more explicitly we understand the movie as one that's about the abolition of slavery and the quest for civil rights (Ta-Nehisi's standard), the less satisfying it is. That is because, although the history of slavery, its abolition, and its long aftermath sure has its liberal moments (of tolerance, progress, and "better angels") it also features plenty of decidedly illiberal ones, including slavery itself, a lethal civil war, the Ku Klux Klan, lynching, murderous attacks on civil rights organizers in the second half of the 20th century, and the persistence of blatant and subtle forms of racism.
To put it another way, it is hard to tell a liberal story that makes audiences feel good while also doing justice to the complexity and difficulty of struggles against slavery and its legacies. Hard but not impossible.
Tony argues that the film is a "radical" contribution to the film history of the Civil War because it doesn't trade in Lost Cause nostalgia or the hackneyed idea of the tragic "brothers' war." I don't quite agree with that interpretation. What I want to emphasize here, however, is that by deciding to focus on Lincoln's struggle to abolish slavery, Spielberg and Kushner ensured that the film would be seen within another history: the history of films about struggles for black civil rights and equality. In that context—with its benevolent white heroes and patient, passive African Americans—the film is decidedly not innovative.
I agree that this is not a reactionary film. It does not repeat many of the historical inaccuracies and white supremacist messages of earlier films about the Civil War. It does not argue that Lincoln was a tyrant or that African Americans were better off in slavery. But isn't that setting the bar awfully low? Aren't we entitled to expect a bit more from people as smart and well-financed (and liberal) as Spielberg and Kushner?
Previously: A.O. Scott: "The underrated radicalism of Lincoln"