Tonight, seven states held their primaries. Overall, the TEA Party had two big victories over establishment candidates in Republican primaries. And healthcare reform’s unpopularity was apparent again.

The most watched race tonight was the Senate Republican primary in Delaware. Marketing consultant Christine O’Donnell upset Rep. Mike Castle (a moderate former governor who sought promotion to the Senate after 18 years in the House) with 53% of the vote. She joins other TEA Party favored GOP Senate candidates like Rand Paul, Sharron Angle, Marco Rubio, and Ken Buck, each of whom defeated the initial favorite of the GOP establishment. Currently, O’Donnell starts off as an 11 point underdog against Democrat Chris Coons, but the election is seven weeks away, so anything can happen, particularly since O’Donnell surged in the last few days before the primary.

In Massachusetts, we have yet another example of the unpopularity of healthcare reform, as nine year incumbent Steve Lynch defeated Mac D’Alessandro, the New England Political Director of SEIU, 65-35%. Rep. Lynch was one of a few northern Democrats (and the only Massachusetts Democrat) to oppose healthcare reform, and this one vote was the basis for the leftist primary challenge. This has to be a disappointing defeat for progressives, who have not defeated a single Democrat who opposed healthcare reform.

New York – 40 year incumbent Charlie Rangel, despite his ethics problems, was renominated with 51% of the vote (his closest challenger, Adam Clayton Powell IV, got 23%). Interestingly, the last time Rep. Rangel had serious primary competition was in 1994 against Powell, whom he defeated 61-33% back then. New York Republican primary voters, however, upset the party establishment by choosing  developer Carl Paladino with 62% over Rick Lazio, a former “up and comer” who was Hillary Clinton’s opponent in Hillary’s first Senate race in 2000.

New Hampshire – (UPDATED 9/15 PM) In this Republican Senate primary, the preferred candidate of the GOP establishment was Attorney General Kelly Ayotte, who also had Sarah Palin’s endorsement. Her main conservative opponent, Ovide Lamontagne, benefitted from a late surge and led with initial returns. However, with 93% reporting, Ayotte pulled ahead later in the night and has been declared the winner with a 38-37% lead.

The untold story of the night, as with other primary nights, was that GOP voter intensity was apparent again. In the five states that had contested statewide primaries on both sides of the aisle, 47% of the voters chose a GOP ballot. This number is especially impressive when you consider that, by and large, these were Democratic heavy states that in the aggregate gave Obama 62% of the vote. In other words, we had a 10% “Obama plunge” (explained here), with greater swings towards the Republicans in New Hampshire (69% voted in the Republican primary) and Wisconsin (56% voted in the Republican primary) – “pale blue” states that Obama/the Democrats can ill afford to lose.

With the exception of Hawaii’s primary this Saturday, primary season has concluded. Overall, 52 House/Senate members retired, while seven Congressional incumbents were defeated in the primary. The big question mark will be how many incumbents will be defeated in November. For comparison’s sake, in 1994, 34 Democratic incumbents (and no Republican incumbents) were defeated.

The one remaining question (as primary season comes to a close) in our mind: what surviving House incumbents/Senate incumbents up for re-election in 2012 will do once the election returns have come in. We believe that several incumbents on both side of the aisle will question whether they want to be on the ballot at the same time as the Presidential race is being held, assuming that they survive their primaries in 2012. A similar dynamic occurred after the 1994 GOP landslide, when 37 Democrats and 27 Republicans eventually retired before the 1996 elections.

Looking ahead, we will be providing weekly polling updates on the House/Senate/Governor’s races. We will also provide updates on early voting in Louisiana (which starts this Saturday and continues until Saturday September 25), as well as the Louisiana “everything else” primary on October 2, which features a hotly contested Lieutenant Governor’s race.