RENO, Nev. (AP) - Republican Sen. Dean Heller and Democratic Rep. Shelley Berkley top Tuesday's primary ballot in a U.S. Senate race expected to produce a general election as hotly contested as the presidential race that Nevada voters will play a key role in deciding this November.
Heller, a popular ex-congressman from a safe rural seat appointed last year after John Ensign resigned in a sex scandal, and Berkley, a seven-term congresswoman running her first campaign outside of metro Las Vegas, faced only token opposition in Tuesday's primary. Polls are open from 7 a.m. to 7 p.m.
Active registered Democrats in Nevada currently outnumber the GOP 41 percent to 37 percent - or 433,096 to 394,304 - but Republicans had the upper hand in terms of absentee ballots and the early voting that closed on Friday. They accounted for 51 percent of those 117,289 votes to the Democrats' 45 percent in the primary contest expected to attract a low turnout - likely fewer than one in five of Nevada's 1.1 million registered voters.
Interest in the Senate race that recent polls show is neck-and-neck is sure to grow by fall, as evidenced by the more than $300,000 a group backed by Karl Rove - once George W. Bush's White House chief of staff - already has spent on ads attacking Berkley's record. Nevada is one of a handful of battleground states expected to determine whether President Obama will hold off Republican Mitt Romney.
In Nevada's other congressional races, freshman GOP Rep. Joe Heck faces an unlikely primary challenge from Chris Dyer in the 3rd district, where outgoing state Democratic Assembly Speaker John Oceguera, of Las Vegas, is expected to advance to the general election. The southern Nevada district is the state's most evenly divided - 39 percent Republican, 38 percent Democrat and 25 percent other.
Republican Rep. Mark Amodei, a former state legislator appointed to fill Heller's unexpired term, has no serious competition in the primary in the rural 2nd district, where no Democrat has ever won.
Heck and Amodei both have endorsed former state Sen. Barbara Cegavske in the newly created 4th district. She faces eight other Republicans including former UNLV basketball star Danny Tarkanian, who previously ran unsuccessfully for Congress and secretary of state.
Republicans Kenneth Wegner, the unsuccessful GOP nominee in the 1st district in 2010, and affluent businessman Dan Schwartz are among the others bidding to advance to the general election against outgoing Democratic Senate Majority Leader Steven Horsford, of Las Vegas, who will be the favorite in the new 4th district with 113,312 active Democrats and 89,857 Republicans.
Democrat Dina Titus, who served a term in the 3rd district surrounding Las Vegas, was unopposed in the bid to replace Berkley in the 1st district, where five Republicans are seeking the GOP nomination but are unlikely to advance any further, given that Democrats outnumber Republicans there nearly 2-to-1.
In races for the state Legislature, there are six Democratic primaries and three GOP primaries that will determine the final list of general election candidates for a dozen state Senate seats. Nevada has 21 state senators, but the other nine seats aren't up this year. Senators serve four-year terms and Democrats currently control the Senate by a bare 11-10 margin.
All 42 state Assembly seats are up for grabs, although nine incumbents face no opposition and have free rides into new two-year terms. In Tuesday's primary, there will be 15 Democrat contests and 13 Republican battles to determine the final list of general election contenders. Democrats currently hold a 26-16 advantage in the Assembly.
Primary voters will also pick finalists for three state Board of Education seats, as well as four seats on the Nevada Board of Regents. Those races are nonpartisan, so if there are three or more candidates the top two vote getters in each district advance to the general election.
Among ballot measures across the state, residents of Laughlin will vote whether to incorporate the Clark County town of about 7,000 near the Colorado River that's a two-hour drive from Las Vegas.
Copyright 2014 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.