Yesterday was primary day in a great many states. It was widely billed as a challenge for incumbents, and as Michael Barone writes:

…[O]ne way to look at the results is that no incumbent member of Congress lost his or her bid for reelection.

But Barone says incumbents don’t have that much to rejoice about, either, because their margins of victory were far less than would be ordinarily expected, and their day of reckoning may merely have been postponed till November 2.

We’ve been anticipating that 2010 election for quite some time now, but in political terms it remains distant. There’s still a lot of money to be spent and name-calling to be done in the five loooong months between now and then.

As Barone points out, the selection of incumbent Blanche Lincoln is an especially interesting phenomenon. She was in big trouble after the passage of HCR, so one might imagine that her primary victory represents a triumph of sorts. Yes and no. She lives to fight another day. But her prospects in November are shaky, at least at the moment. She won yesterday, but not by much for an incumbent.

And conservatives have something to cheer about in her win, because it represents a defeat for the labor unions and especially their pet project card check. Unions put big money behind Lincoln’s Democrat opponent in the primary, Halter. Lincoln had ended up opposing card check, knowing it was very unpopular in her state of Arkansas and would impact negatively on businesses there. As Barone observes:

Big labor decided to teach her””and all Democratic members of Congress who were quailing at the prospect of voting for card check””a lesson. The lesson would be that, however much a vote for card check would reduce your chances of winning a general election, opposition to card check would result in your defeat in a Democratic primary. Their ready and willing instrument was Bill Halter, whose path to higher office seemed otherwise occluded. At the beginning of March he announced his candidacy and proclaimed himself the champion of the working man. Blanche Lincoln, in agonized response, proclaimed herself the target of outside interests. In a matter of weeks labor unions and moveon.org””originally formed to defend Bill Clinton against impeachment””sent millions to Bill Halter’s campaign.

To no avail. By winning her relatively narrow victory, Lincoln thwarted union plans to effectively threaten the primary victories of candidates around the country who oppose card check:

It’s a huge defeat for the unions. White House political operatives are already complaining, as Ben Smith notes in Politico, that “Organized labor just flushed $10 million of their members’ money down the toilet on a pointless exercise,” [a senior White House] official said.

I couldn’t be happier about that loss of cash, although I have sympathy for the (sometimes involuntary) union members who have no say in how their dues money is used politically after it is extracted from their hands (see this for my opinion of card check). It is a special and delicious irony that the only reason unions were able to spend this sort of money to try to unseat Lincoln was the Supreme Court decision in Citizens United, a ruling previously excoriated by the left as tending to help big business. Funny thing, that.

In other primary news, Harry Reid can heave a small sigh of relief at the Nevada Republicans’ selection of Sharron Angle, tea-party-backed candidate whose especially conservative views and associations will be fully exploited by the Reid camp in the months to come. It may not matter, however; Reid remains deeply unpopular. But Angle’s victory reminds us that party primaries don’t always lead to the strongest candidates the party might offer.