Michael Kinsley is on to something when he argues,  in a recent post at the Washington Monthly's Ten Miles Square Blog, that people ought to check the logic of arguments in politics.  He's completely wrong, however, to suggest they shouldn't also check facts (but maybe this was a title he didn't assign–"Check Logic, Not Facts").  He writes:

This political campaign has been a frustrating blizzard of numbers and studies.

One side says $344 billion over 21 years, then the other side calls that a desperate lie and says the real number is up to $1 trillion over the next decade. The first side then attempts to validate its number by saying it comes from a recent report by the authoritative Center for Boring Statistics, and the second side says that, by contrast, its numbers are based on the nonpartisan volume “Vicious Figures for Dummies, 3rd Edition” (1958).

How is a citizen supposed to know whom to believe?

Journalism might help sort out which ones are credible. Anyway, on to the importance of logic: 

There is an alternative. Many campaign thrusts and parries can be verified or discredited by reason and logic alone. They just don’t make sense (or, on occasion, they do make sense) without reference to any numbers or studies. Reason doesn’t require the approval of the Congressional Budget Office. It is available to anybody willing to take a minute and use it. And it is self-validating. You don’t need to trust anybody to decide whether reasoning is true or false.

For example, you don’t need any actual numbers to figure out that Republican presidential nominee Mitt Romney and his running mate, Representative Paul Ryan, are talking through their hats about Medicare and Social Security.

Minor quibble: reasoning isn't really true or false, it's sound or unsound, valid or invalid, etc.  That distinction, between inferences and facts, is actually a critically important one to Kinsley's point.  And his flubbing up the correct terminology shows that he really doesn't have a grip on what makes his recommendation, admirable though it is, very difficult to implement.

For people hide behind inferences all of time as matters of opinion.  It's their opinion, they may argue, that A follows from B.  Kinsley needs to find a way to show that it is not a matter of opinion that A follows B.  But that's difficult to do.  It's way more difficult than checking facts.