I thought it would be illuminating to illustrate the "success" of the establishment class of the Democratic party represented by folks like Martin Peretz, Joe Lieberman and others in graphical form.
If I were a Republican I’d urge the Dems to keep up the good work.

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Peretz’s point, which you neglected to see, is that when Dems radically shift towards the left and get into bed with the “peace” movement, then they lose. Huge.
This is evidenced by … your very own graph! Peretz mentions George McGovern in 1972 as the ultimate peace candidate. According to you, the Dem’s had their lowest % of the popular vote in …..
I would argue that the peacenik Dems of the 60s and 70s would find modern Dems like me who support armed intervention in Yugoslavia, Iraq in the 90s and Afghanistan in 2001 as a bunch of warmongers. Peretz’s “choice” is a false one. To continue with the failed Iraqi policies and for Democrats to enable it weakens America and inhibits our ability to use force when necessary.