Ramesh Ponnuru previews the vice presidential debate, and gets something important wrong:

Agree with Ryan or not on foreign policy, he is fluent on it even if it hasn’t been the focus of his career.

I’m not sure why a Ryan supporter would say this. Granted, Republicans and movement conservatives don’t want to advertise the fact that Ryan doesn’t have much foreign policy experience, but it doesn’t help their candidate to pretend that he knows these issues very well. Based on his public speeches on this subject, we see that Ryan can capably recite his party’s prevailing views. He has a few favorite themes that he keeps revisiting, such as his universalist preoccupation with the threat of “moral relativism” in foreign policy. The rest of us call this prudence, but never mind that. Biden’s record is quite poor, but that isn’t a debate Ryan wants to have. If Biden’s record is marred by poor judgment (usually when he has taken hawkish positions), and it is, Ryan’s record on foreign policy consists of little besides supporting Bush administration wars and decisions. That’s to be expected, since Ryan was first and foremost a “team player” during the Bush years, but that suggests that Ryan’s judgment is at least no better than Biden’s and might be worse.

Even if the VP nominees could fight each other to a draw on this point, they will still have to address the presidential nominees’ arguments and their respective agendas. The real problem for Ryan will be defending his running mate’s positions against Biden’s attacks. Biden has already had some fun ridiculing Romney’s fixation on Russia, and when questioned about this in the last few weeks Ryan has not done a particularly impressive job of refuting criticisms of Romney’s views on Russia policy. Ryan has been comfortable making the usual attacks on Obama’s supposed “appeasement,” but once he makes the attack he doesn’t seem to be conversant with the relevant issues to make a persuasive case. Some might say that there is no case to made regarding such “appeasement,” since it hasn’t happened. That points to another weakness that Ryan’s arguments share with Romney’s on these issues: they are directed against an imaginary record. Even if Ryan were better-versed and more experienced in foreign policy than he is, it would be very challenging to make so many unfounded charges stick. That doesn’t mean that Ryan will be perceived as losing the debate because of this part of it, but his supporters shouldn’t expect him to be “fluent” in something he doesn’t know that well.