Jackson, Mississippi (CNN) -- With 100% of precincts reporting results, CNN can report that the Mississippi Republican Senate primary is headed for a June 24 runoff.
Sen. Thad Cochran and Chris McDaniel will battle again after both candidates fell short of the 50% threshold needed to avoid another contest.
The race is a high-profile tea party vs. establishment showdown. For tea party supporters, it's perhaps their best chance to claim victory after facing a string of defeats this year.
Tuesday marked the biggest single day of primary voting in 2014, with contests in eight states.
In Iowa, the winner of that high-profile GOP Senate primary had rare support from both sides of the battle between conservatives and the establishment.
If Republicans can flip the Hawkeye State and five other Democratic-held seats, they will regain control of the Senate.
And California used its new "jungle" primary system for the first time in a gubernatorial race. That's where the top two finishers advance to the November election, regardless of party affiliation.
With Democratic Gov. Jerry Brown the overwhelming favorite, the race was for second place, and a moderate Republican edged out a tea party-backed conservative state lawmaker.
At 76, Cochran is the second-oldest Senate incumbent running for re-election. McDaniel, a state senator, ran on a platform of change, saying Cochran, who has served in Congress for four decades, has been in Washington long enough.
"We don't have six more years of the status quo," he recently told CNN. "I am not going to Washington, D.C., to be a member of the cocktail circuit or to make backroom deals. I'm going up there to fight and defend the Constitution."
Cochran and McDaniel were separated by fewer than 1,400 votes with McDaniel slightly ahead, 49.5% to 49%, according to numbers compiled by The Associated Press. A third Republican candidate in the primary race, Thomas Carey, grabbed 1.5% of the vote.
So what happens next?
The two candidates have a little under three weeks before they go head to head again.
Runoffs usually have lower turnout and tend to favor challengers.
Money will be key as both dig deeper into their campaign war chests and rely on outside help from independent groups.
McDaniel's campaign was already asking for more cash Wednesday.
"I'm going to be brutally honest with you: our campaign is pretty low on money and there's no way we can win if conservatives from around Mississippi and America don't stand up and make sure we have the resources we need to win," he said in an email blast.
FreedomWorks, a national tea party group that backed McDaniel, pledged to "double down" on its efforts to make sure he wins.
Another conservative group, Club for Growth, even called on Cochran to drop out, but vowed to "vigorously pursue this race" in support of McDaniel no matter what.
Cochran supporters also say they're ready for another round.
Henry Barbour, who runs the pro-Cochran PAC Mississippi Conservatives, told CNN's Dana Bash that they're "going to get up and rethink" their message. "Really organize from the ground up," he added.
Barbour said "complacency" among Cochran voters "hurt us" and he thinks "they got outshouted."
His group dished out six figures to support Cochran, who was also backed by the U.S. Chamber of Commerce, which represents the interests of business.
The chamber put out a statement in support of Cochran on Wednesday, but declined to specify if it will go up with another ad buy.
Another leading outside group that tends to support establishment candidates, American Crossroads, said it would stay out of any runoff.
Stuart Stevens, a Cochran adviser and former adviser to Mitt Romney, told Bash that three weeks allows more time to scrutinize McDaniel's record and ask tough questions.
The winner will face off against former Rep. Travis Childers, who CNN projects will be the Democratic nominee, in November.
State Sen. Joni Ernst didn't have to take sides in the battle between grass-roots conservatives and the Republican establishment: She had the backing of both, and she easily came out on top in a crowded primary race.
Ernst, a lieutenant colonel in the Iowa National Guard who grabbed national attention by touting her hog castrating skills in a campaign commercial, had the support of some top names and groups among both the tea party movement and the mainstream GOP.
At her victory party Tuesday night, Ernst acknowledged and thanked her GOP competitors.
"It is going to take all of us pulling together to unite this party and win in November," she said.
The race was originally a free-for-all between four major GOP candidates, but in the closing weeks of the campaign, Ernst pulled ahead of her rivals.
The big question going into primary day was whether she would top 35%. If no candidate passed that threshold, the nomination would have been decided a week later by delegates at the Iowa GOP convention. But in the end, Ernst won in a landslide.
Ernst will face off against Democratic Rep. Bruce Braley, who had no opposition for his party's nomination.
The winner of November's general election will succeed longtime Democratic Sen. Tom Harkin, who is retiring at the end of the year.
Republicans believe they have a good shot at flipping Harkin's seat.
Big-name Republicans from both the establishment and conservative wings of the party, like Mitt Romney, Marco Rubio and Sarah Palin, joined Ernst on the trail.
She also grabbed support from the Chamber of Commerce and the National Rifle Association as well groups like the Senate Conservatives Fund, which often backs like-minded candidates who launch primary challenges against incumbent Republican senators.
California gubernatorial race
Brown and Republican Neel Kashkari finished in first and second place, respectively, and will advance to the general election.
Brown's first-place finish was never in doubt. Kashkari and fellow Republican Tim Donnelly were vying for the second spot.
Some GOP strategists said they were concerned that if Donnelly, a conservative with tea party backing, had won, it could have hurt Republican candidates come November in down-ballot races in a state where the general election electorate is much more moderate.
Kashkari, a moderate, was a Treasury Department official under President George W. Bush.
One time anti-war protester Cindy Sheehan was also on the ballot, the nominee of the Peace and Freedom Party, a socialist party. She grabbed about 1% of the vote.
Sheehan became the face of the anti-Iraq war movement in 2005 when she protested for weeks outside Bush's ranch in Crawford, Texas, after her son Casey was killed in combat.