In two contested primary elections on Tuesday, both Democrats and Republicans got the stronger general election candidates in California and Iowa districts that have provided close vote totals in recent years. In Iowa, six-term Rep. Leonard Boswell won renomination, while in California, State Senator Tom McClintock bested two GOP rivals in the race to replace outgoing Rep. John Doolittle.

Iowa's Third District, centered around Des Moines, has proven increasingly competitive in recent cycles. After winning a narrow contest for an open seat in 1996 by a single point, Boswell faced tough Republican challengers in 2004 and 2006, winning last cycle by just six points.

This time, though, the challenge came from the left, as former State Rep. Ed Fallon, who placed third in the state's gubernatorial primary in 2006, urged Democratic voters to kick out the more centrist Boswell. Fallon, who endorsed Barack Obama in the state's January caucus, hoped to capitalize on the change message that gave the Illinois Senator a majority in the district. Boswell had backed Clinton in that race.

Boswell outraised and outspent his Democratic rival and ended up with a reasonably healthy 61%-39% win, and in time he turned Fallon's presidential endorsement argument around: Boswell made an issue of Fallon's 2000 endorsement of Ralph Nader over Al Gore, as the Des Moines Register reports today.

Boswell now heads to the general election against former congressional staffer and administrative law judge Kim Schmett. The Democrat has faced tougher competition in the past, and this year he looks like a safe bet for re-election.

In California's Fourth District, McClintock scored a 53%-39% victory over former Rep. Doug Ose, who spent nearly $3 million of his own money on the primary. McClintock, though, has become a conservative icon in California after narrowly losing the Lieutenant Governor's race in 2006. A third candidate won 2% of the vote.

McClintock will run against 2006 nominee Charlie Brown, a Democrat who came within three points of ousting the ethically troubled Doolittle that year. While Democrats were confident about their chances against the incumbent, running against McClintock will prove more troublesome. A recent poll for Brown showed him leading McClintock by two points, but both candidates scored only in the low 40s.

With a new nominee whose house has not been raided by federal agents, as Doolittle's was in 2007, Republicans have a much stronger chance of retaining what is ordinarily a heavily Republican seat. President Bush won the district, which encompasses the Sacramento suburbs, by wide margins in both his elections.