MINORITY LEADER PELOSI makes a different excuse for Blue Dog Democrats, because she won’t stand up for unions any more than Pres. Obama and the Democratic Party will. We saw that in Wisconsin, where even Democrats didn’t choose the union candidate to take on Scott Walker.

Of course, that hasn’t kept unions from being the Democratic Party’s whipping post. If you don’t have to earn a vote because it’s in the bag, why work for it?

But why should any Democrat attend this year’s convention?

It’s supporting right-to-work over unions, as well as the Democratic Party’s continued shift to economic austerity and corporatism over organizations that helped build and make the middle class possible.

Why Democrats need labor unions, By Julian Zelizer

[…] Union leaders frequently complain that they have second-class status in the party compared with other groups such as environmentalists or suburban voters. During the battle over public employee unions in Wisconsin, most national Democrats were noticeably absent from the debate. Before the Wisconsin gubernatorial election that followed the recall, President Obama was willing to tweet his support for Gov. Scott Walker’s opponent, Tom Barrett, but unwilling to actually visit.

This fissure has high costs for the Democrats and for liberalism more generally. Organized labor has been integral to the organizational strength of liberalism throughout the 20th century, as the most reliable and powerful force to get out the vote in elections and to help build congressional coalitions behind progressive legislation.

The alliance, which formed when the AFL helped President Woodrow Wilson during the early stages of World War I, flourished during the New Deal. Democrats won the support of workers as a result of the surge of legislation that helped working- and middle-class Americans find economic security.

The Wagner Act (1935) cemented this marriage as the federal government legitimated the right of workers to organize in unions. Labor leaders like Sidney Hillman from the Amalgamated Clothing Workers of America, who helped found the CIO, established the first political action committee to help FDR win re-election in 1944. During World War II, most of the major unions were a key part of the homeland effort, assisting the administration as it moved to convert factories to wartime production.

In 1948, President Harry Truman would not have won re-election had it not been for organized labor, which in the final weeks of the campaign mobilized its troops to defeat New York Gov. Thomas Dewey. “Labor did it!” cried Truman, who won the vote of 89% of the automobile workers, recounted historian Nelson Lichtenstein. […]

This piece has been updated.