Tu Quoque arguments, it seems to me, have a statute of limitations on when the first of the two inconsistent acts can be relevantly inconsistent with the second. (See my long article in Informal Logic for the full story)  For example, someone may express appropriate surprise at the fact that the altarboy later became an atheist when he was a grownup, but that's not inconsistency in the relevant sense for an accusation of hypocrisy.  The two acts need to be close enough in time for them to be relevant to each other.  And so it's usual when someone runs an argument from inconsistency, she will say something like:

Person S says we should not do X, but then she turns right around and does X.

The important thing is that S turns right around and does it.  If she did X years ago, perhaps S has learned her lesson.  Or she's changed her mind.  Or maybe the facts regarding X have changed.  X may be the best option, nowadays.  The lesson: with charges of hypocrisy, time's relevant.

With that in mind, let's look at Jonah Goldberg's commentary on the (albeit grudging) praise of Ronald Reagan's presidency from liberals.  This is part of a trend he sees. Barry Goldwater, after being demonized by LBJ, was later portrayed as an "avuncular and sage grandfather type." William F. Buckley, too, went from being called a Nazi to later being an actual defender of liberalism.  Reagan, now:

As we celebrate the 100th anniversary of his birth, the Gipper is enjoying yet another status upgrade among liberals. Barack Obama took a Reagan biography with him on his vacation. A slew of liberals and mainstream journalists (but I repeat myself) complimented Obama’s State of the Union address as “Reaganesque.” Time magazine recently featured the cover story “Why Obama (Hearts) Reagan.” Meanwhile, the usual suspects are rewriting the same columns about how Reagan was a pragmatist who couldn’t run for president today because he was too nice, too reasonable, too (shudder) liberal for today’s Republican party.

Trouble is, while Reagan was alive, liberals didn't have too high an opinion of him:

[My] favorite comes from Madame Tussauds Wax Museum in London, which in 1982 held a vote for the most hated people of all time. The winners: Hitler, Margaret Thatcher, Ronald Reagan, and Dracula.

Now, first, note that these are cases where we're looking at things said in 1982 and 2011.  Almost thirty years difference.  Second, note that these inconsistencies are ones distributed over a group, Liberals, not individual people.  Regardless, it's almost as though Goldberg isn't paying attention to the subtext of these retrospectives:  that despite the fact that liberals disagreed with these conservatives, liberals could nevertheless see their virtues as people in retrospect.  And one of the reasons why those virtues are worth mentioning now is that current conservatives so clearly fail to have them.  I take it back.  Goldberg gets that part:

[S]o much of the effort to build up conservatives of the past is little more than a feint to tear down the conservatives of the present.

But, for some reason,  he thinks instead this is a point he's scoring on liberals by showing how they're inconsistent.  Again, in cases where time's changed the variables, sometimes what you've inveighed against earlier becomes the best choice.  Ask any liberal: would you take  Reagan or Buckley over Palin or Goldberg for a decent conversation about government and political norms?  You know the answer.  Goldberg thinks this means that liberals think that the only good conservative is a dead conservative. He's missed the point.  The point, instead, is sadly that all the good conservatives are dead.