Delaware Republican Senate candidate Rep. Mike Castle answers a question during a town hall meeting in Philadelphia on Aug. 31, 2009. (AP File Photo/Matt Slocum)
Washington (AP) - The primary season is ending as it began, with the Republican establishment on one side in state after state, and tea party activists on another.
The competition is particularly strong in Delaware and New Hampshire, where GOP senatorial nominations are the prize, and New York, where Republicans pick a challenger for an uphill fall campaign for governor.
Rhode Island, Massachusetts, Wisconsin and Maryland also hold primaries Tuesday, along with the District of Columbia.
Among incumbents, veteran Democratic Rep. Charles Rangel of New York and Washington Mayor Adrian Fenty face particularly stiff challenges -- one because of ethics charges in Congress, the other after conceding to voters he has behaved arrogantly over the past four years.
In Delaware, veteran Rep. Mike Castle, a moderate, vies with Christine O'Donnell for the nomination for a Senate seat. O'Donnell has the support of former Alaska Gov. Sarah Palin as well as tea party activists. New Castle County Executive Chris Coons has no opposition for the Democratic nomination.
In New Hampshire, Democratic Rep. Paul Hodes is unopposed for the Senate nomination, and Republicans are settling a multi-candidate race. Former Attorney General Kelly Ayotte campaigned with the support of the party establishment and Palin, while Ovide Lamontagne claimed backing from tea party activists. Bill Binnie and Jim Bender campaigned on the strength of their records as businessmen.
In Maryland, former Republican Gov. Bob Ehrlich faces a primary challenge from Brian Murphy, 33, a business investor who was virtually unknown before winning Palin's endorsement last month.
Democratic Gov. Martin O'Malley, who ousted Ehrlich from office in 2006, faces minor opposition for the nomination to compete for a new term.
Wisconsin Republicans are choosing among three candidates to pick a challenger for Sen. Russ Feingold, and businessman Ron Johnson is widely viewed as the prohibitive favorite.
In Rhode Island, Providence Mayor David Cicilline, who is openly gay, campaigned in a three-way race for the Democratic nomination to run for the seat being vacated by Rep. Patrick Kennedy. Republicans are having a contested primary to select their own candidate.
New York Attorney General Andrew Cuomo is unchallenged for the Democratic gubernatorial nomination. Republicans are choosing between former Rep. Rick Lazio, backed by party officials, and Carl Paladino, a wealthy developer who campaigned with support from tea party activists.
So far this year, seven incumbent members of Congress -- four Republicans and three Democrats -- have been defeated in primaries. In addition, party-backed candidates have been defeated in Republican contests in Nevada, Colorado, South Carolina, Kentucky and elsewhere.