In Washington state, freshman Democratic Sen. Maria Cantwell, considered by some to be vulnerable in November, and her GOP challenger, Mike McGavick, were expected to blow past their little-known rivals in their respective primaries.
Massachusetts' Deval Patrick, 50, who headed the Justice Department's civil rights division under President Clinton, led in the most recent polls against Boston venture capitalist Chris Gabrieli, 46, who spent more than $8 million of his own fortune on the campaign, and state Attorney General Tom Reilly, once the prohibitive favorite.
If Patrick won in November, he would be just the second black elected governor in the United States, after L. Douglas Wilder of Virginia in 1989. However, no Democrat has been elected governor in this bluest of blue states since Michael Dukakis 20 years ago.
On the GOP side, Republican Lt. Gov. Kerry Healey faced no opposition for the nomination for governor.
Republican Gov. Mitt Romney decided not to seek re-election and is instead considering running for president in 2008.
Reilly, 64, started the year as the front-runner, but took a beating after he acknowledged calling a district attorney investigating the alcohol-related crash of the daughters of a campaign donor. Then the state lawmaker he picked as his running mate quit after one day, following disclosure of unpaid taxes and student loans.
The Democrats clashed over taxes and immigration, with Patrick warning that a cut in income taxes would put pressure on property taxes and backing a proposal to allow the children of illegal immigrants to pay in-state college tuition rates.
In Washington state, Cantwell, like Connecticut Sen. Joe Lieberman, faced a revolt from anti-war activists in her party. But she tried to distance herself from her vote in favor of the Iraq war, and she neutralized an anti-war rival by hiring him to join her campaign.
She was seen as the prohibitive favorite in the field of five Democrats. McGavick, a former insurance executive, was expected to roll over five GOP rivals.
The state generally leans Democratic, and Cantwell is favored in November.