The big news of the day is that Barack Obama has picked up enough superdelegates, along with delegates pledged to John Edwards, to clinch the presidential nomination.

I’ve been trying to tell people at Daily Kos for months that the superdelegates would bring down the curtain after all the states had voted.

I think the extended primary season was on balance excellent for the Democratic Party, and I couldn’t disagree more with those who have been badgering Hillary Clinton to drop out for the past two or three months.

Early returns from South Dakota indicate that Hillary will win that primary, by the way.

Polls close soon in Iowa, and I will update this diary when I have some results to report.

UPDATE: With 46 percent of precincts reporting Boswell leads Fallon 56 percent to 44 percent. Not clear whether absentee ballots have already been counted. I would expect Boswell to have an edge there. Also not clear whether the big Des Moines precincts have reported.

UPDATE 2: Not looking good for Fallon–Boswell leads 57-43 with 60 percent of precincts reporting.

The GOP Senate candidates are bunched closely together with 25 percent of precincts reporting.

Still only 4 percent of precincts reporting in IA-04. Greenwald leads, but it’s way too early.

Peter Teahen is ahead in the GOP primary in IA-02 wih 30 percent of precincts reporting.

UPDATE 3: The Des Moines Register has called the IA-03 primary for Boswell. He leads 60-40 with 90 percent of precincts reporting.

Becky Greenwald has a huge lead in IA-04, with 52.6 percent of the vote after 59 percent of precincts reported. Kurt Meyer is in second place with 26.6 percent; William Meyers has 12.1 percent, and Kevin Miskell has 8.7 percent.

Mariannette Miller-Meeks has a small lead over Peter Teahen, 44.3 percent to 42.3 percent with 82 percent of precincts reporting.

The GOP Senate race is very close with 79 percent of precincts reporting: Christopher Reed has 35.4 percent, George Eichhorn has 34.9 percent.

UPDATE 4: There may need to be a recount in IA-02. With 98 percent of precincts reporting, Miller-Meeks leads Teahen by fewer than 100 votes, 43.5 percent to 43.0 percent.

The GOP Senate primary is also a squeaker, with fewer than 200 votes separating reed and Eichhorn.

Boswell leads Fallon 61-29 with 98 percent reporting.

Greenwald leads Meyer 51-27 with 84 percent reporting.

All the Democratic House incumbents who had primary challengers held on to their seats.

Jerry Sullivan won the primary in House district 59 with 78 percent of the vote despite the robocalls against him that I wrote about last night.

FINAL UPDATE: It looks like Obama won the Montana primary and Clinton won the South Dakota primary.

I didn’t see Obama’s speech to a huge crowd in the Twin Cities, but I am amused that John McCain stupidly scheduled a speech for this evening. His speech got cut off so the tv networks could devote coverage to the big story (Obama winning the nomination) and Obama’s big speech (which was apparently great).

In IA-03, Boswell beat Fallon by 61-39 percent with all the precincts in. That is comparable to Representative Jane Harman’s victory over Marcy Winograd in a California Congressional district two years ago. Harman’s voting record reportedly improved after that primary. Let’s hope we can expect the same from Boswell.

Final results from the IA-04 primary: Greenwald 50.7 percent, Meyer 27.6 percent, Meyers 13.2 percent, Miskell 8.4 percent.

Christopher Reed won the GOP Senate primary by about 400 votes out of about 70,000 votes cast. He had 35.3 percent of the vote, George Eichhorn had 34.7 percent, and Steve Rathje had 29.9 percent.

IA-02 race called for Miller-Meeks. She won by a margin of 109 votes out of nearly 17,000 votes cast.

Nothing on the Des Moines Register’s site about recounts in the GOP Senate primary or Congressional primary in IA-02.