WASHINGTON - Republicans count enough competitive races to challenge Democrats for control of the Senate in the 2014 elections, if only they can figure out what to do with the tea party.

Crowded primaries in states such as Georgia, Iowa, and North Carolina, where tea party backers and social conservatives are fighting for the nomination and pushing candidates farther right, worry many Republicans, especially after they saw their legitimate shots at a Senate majority slip away in 2010 and 2012.

Republicans need a net gain of six seats to capture control from Democrats, who effectively hold a 55-45 advantage now. But Democrats will be defending 21 of 35 seats to be decided in November, and President Obama is looking like a major drag for them. Midterm elections are often tough for a president's party in any event.

Republicans inside and outside the Senate speak confidently about snatching open seats in West Virginia and South Dakota. They like their chances against Democratic incumbents in Republican-leaning Arkansas, Louisiana and Alaska and remain upbeat about Montana even if Democratic Gov. Steve Bullock names Lt. Gov. John Walsh to succeed Sen. Max Baucus, Obama's choice for U.S. ambassador to China.

The looming question is whether Republicans undercut their solid shot with tea party-style candidates who fizzled out in Delaware, Colorado, and Nevada in 2010 and Indiana and Missouri in 2012.

Georgia is keeping some Republicans awake at night. Eight candidates, including three House members, are pursuing the open seat of retiring two-term Sen. Saxby Chambliss in a state that dramatically went Republican in 1994 and rarely has looked back. Georgia hasn't elected a non-incumbent Democrat since 1998.

A loss of the GOP seat would complicate any Republican math for a majority.

Republicans are nervous about Rep. Paul Broun, who has said evolution and the big-bang theory are "lies straight from the pit of Hell." Although the four-term Georgia congressman has avoided incendiary comments in his latest campaign, several Republicans privately fret about him winning the nomination.

Looking to seize the edge in the free-for-all primary, Broun recently pounded rival Rep. Jack Kingston, considered more moderate, after Kingston suggested that Obama's health care law could be fixed.

In the North Carolina race, Senate Republicans have been raising money for Thom Tillis, speaker of the state House. Tillis faces challenges from Greg Brannon, a physician who has the backing of Sen. Rand Paul (R., Ky.), and has been seeking the support of the tea party and Rev. Mark Harris, a Baptist minister who was instrumental in the state fight to ban gay marriage.

Iowa seemed like a prime opportunity for Republicans after five-term Democratic Sen. Tom Harkin announced he would not seek another term.

Republicans also see a potential to expand the field from the top tier races to contests in Michigan and Minnesota.