Austin, Texas – Ted Cruz has grown accustomed to having his campaign speech interrupted by whoops and hollering, shrieks of "Go Ted!" and even an "A-Men!" or two.
The tea party favorite for a U.S. Senate seat from Texas has come a long way since he kicked off his campaign more than a year ago with seemingly no chance of competing against the GOP front-runner in the race, Lt. Gov. David Dewhurst.
With the backing of national conservative groups and a fiery stage presence that has made crowds across the state swoon, Cruz has pushed himself into the spotlight and sparked speculation about whether he's ready to pull off perhaps the nation's biggest upset this year.
But as the runoff election on July 31 approaches, Cruz faces a difficult obstacle - the solid base of support the 66-year-old Dewhurst has built among Texas conservatives during his 13 years in politics, including nine overseeing the state Senate.
In many areas where Cruz holds his high-energy rallies, Dewhurst is already a known quantity, and local party officials and state lawmakers already have pledged to support him.
"You very quickly realize that no single human being can possibly communicate with 25 million people spread across the state of Texas," Cruz, 41, said in a recent interview, reflecting on his efforts to become known through hundreds of appearances at GOP women's group meetings, candidate forums and Bible study groups.
Although tea party candidates have taken down some mainstream Republicans in conservative states, most recently in Indiana, where ultraconservative Richard Mourdock defeated veteran U.S. Sen. Richard Lugar, the Texas race illustrates the disadvantages many still face in campaigns against established and well-organized officeholders.
"There are a lot of people who don't show up at rallies or write letters or stage protests," said Jonathan Neerman, a Dewhurst supporter and past chairman of the Dallas County Republican Party, referring to the lieutenant governor's network of support. "But that doesn't mean they don't vote."
Among those helping Dewhurst is Texas' popular governor, Rick Perry, who has produced television and web spots for Dewhurst and sang his praises on Fox News Channel.
Dewhurst also has formal endorsements from a list of state senators and organizations, including the Texas Farm Bureau and the National Association of Realtors, which are available for help with phone banks, fundraising and get-out-the-vote efforts.
Texas elected officials have been slower to embrace Cruz - though he has won the support of former Alaska Gov. Sarah Palin and Kentucky Sen. Rand Paul, both tea party superstars.
Further complicating matters for Cruz is that he and Dewhurst don't disagree on much, mirroring each other's positions on key fiscal and social issues and foreign policy. Both oppose President Barack Obama's health care overhaul - Dewhurst says he'd repeal "every word of Obamacare," while Cruz vows to wipe out every syllable.
Cruz, a former state solicitor general, former Ivy League debating champion and son of a Cuban immigrant, is counting on the enthusiasm of tea party supporters and on his ability to deliver the ultraconservative message to get voters to turn out in the dog days of summer, when turnout may be very low.
"This was our hope and it was the objective. It just didn't always seem possible," he said, referring to his whipping up crowds. "When I started, I was at 2 percent in the polls, and the margin of error was 3 percent."
Dewhurst has crisscrossed the state to campaign, but the energy company mogul has a halting speaking style that doesn't inspire public fervor. He has relied on his record to speak for itself.
"I'm simply running for the United States Senate saying that I want to accomplish the same things that I've done in Texas," Dewhurst says.
In overseeing the state Senate, he helped win approval of deep spending cuts to deal with the state's recent budget shortfalls, as well as bills requiring women to undergo a sonogram before having an abortion and voters to show photo identification at the polls - both very popular with the GOP's conservative base.
Dewhurst's connections in Texas business and politics are reflected in his fundraising. The lieutenant governor has received nearly $5.4 million, about 90 percent of it from donors in the state. Cruz has raised about $6 million, about 30 percent from out of state.
Dewhurst, whose personal wealth exceeds $200 million, has lent his campaign over $10 million and hasn't ruled out spending more. Cruz has gotten millions from South Carolina Sen. Jim DeMint's Senate Conservatives Fund, the anti-tax Club for Growth and former Texas Rep. Dick Armey's FreedomWorks - all of whom say Dewhurst is too moderate for sometimes compromising with Texas Senate Democrats to get key legislation approved.
Dewhurst's network of supporters helped him beat Cruz 44 percent to 34 percent in the May 29 primary. He fell about 70,000 votes short of winning the nomination outright in a field of nine Republicans running to succeed retiring Sen. Kay Bailey Hutchison.
Dewhurst and Cruz are campaigning hard in the Dallas area to win over supporters of the third place finisher, former Dallas Mayor Tom Leppert, who hasn't endorsed either. But getting voters to the polls at all will be a challenge, said Neerman, the former Dallas GOP chairman.
"In the summer in Texas," he said, "folks are more worried about their trips to Colorado and Disney World and the lake than they are going to vote."