The Democratic National Committee recently ran an ad blasting John McCain for saying the country is "better off" than in 2000. Yet, arguably, except as regards the Iraq war, Mr. McCain's statement is true. In turn, Mr. McCain is blasting Barack Obama for suggesting that international tensions are not as bad as they've been made to seem. Yet, arguably, Mr. Obama is right.

Democratic attacks on Mr. McCain and Republican attacks on Mr. Obama both seek to punish impermissibly positive thoughts. At a time when there exists a sense...