With a battle brewing for control of the U.S. Senate, voters chose challengers to senators in Maryland, Ohio and California, where Republicans hope to build on recent victories and unseat two-term Democrat Barbara Boxer.

In California, GOP voters nominated a former secretary of state on Tuesday. In Maryland, they chose a deep-pocketed former bond trader in hopes of defeating three-term Democrat Barbara Mikulski (search). In Ohio, Democrats put up a state senator against Republican George Voinovich (search).

The fight for the narrowly divided Senate — with 51 Republicans, 48 Democrats and one independent senator — will bring contentious fall battles. But probably not in these three states.

Democrats face a difficult fight to win back control, complicated by the retirement of Southern Democrats in Florida, Georgia, South Carolina and North Carolina, where John Edwards (search) chose instead to run for president.

California Republicans nominated former Secretary of State Bill Jones (search), who had received the endorsement of GOP Gov. Arnold Schwarzenneger (search). Encouraged by the successful recall of former Democratic Gov. Gray Davis, the GOP targeted the proudly liberal Boxer.

In Maryland, Republican state Sen. E.J. Pipkin's (search) personal fortune — he's a former Wall Street bond salesman — gave the GOP some hope to unseat Mikulski, the longest-serving woman currently in the Senate.

Voinovich, seeking his second term, will face Democratic state Sen. Eric Fingerhut (search).

In House races, former GOP Rep. Robert "B-1 Bob" Dornan (search) flopped in his bid to return to Congress, losing to a fellow California Republican, eight-term Rep. Dana Rohrabacher (search). Dornan earned the nickname for his fierce support of military programs in his district.

Dornan was first elected to Congress in 1976 and served almost continually for the next 20 years. He all but retired from politics after losing back-to-back congressional campaigns in 1996 and 1998.

Few if any House incumbents Tuesday faced a serious threat in the nation's first primary elections to choose nominees for state and local office. Republicans currently hold a 228-205 advantage in the House.