I rather think that the Weekly Standard had very little effect on the vote. I doubt that you can find ten voters among the supporters of Webb, Ford, and Tester who were even slightly influenced by the stories on these candidates.
Perhaps not the magazine. But, Kristol and Barnes were all over Fox News the last two weeks before the election, and neither was doing anything to promote George Allen, Bob Corker, Conrad Burns, or Jim Talent.
Meanwhile, Webb, Ford Junior, Tester, and McCaskill were receiving either kid-glove or regal treatment throughout the cable and network "news".
It's not just The Weak-ly Standard per-se. It's the whole neo-con mindset, which is to make sure Republicans eat their own.