Texas Senate runoff expected to be close

(CNN) – In an election year with notable Senate primary upsets, Texas may well be the next state with a narrative ending in victory for a conservative grassroots underdog.

Voters head to the polls Tuesday to choose between Lt. Gov David Dewhurst, Gov. Rick Perry's number two for nearly a decade, and Ted Cruz, a former solicitor general making his first run for office.

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Heading into Election Day, the Texas political scene is buzzing over some polls showing Cruz, a tea party favorite, with an advantage over the more widely-known Dewhurst. However, Dewhurst's campaign points to an internal poll that indicates their candidate has a narrow margin over Cruz.

Both campaigns say they feel confident about the early voting turnout, with Cruz's team urging one final push.

"All indications are that our voters are excited and encouraged, but now's not the time to let up. We need every conservative across the state who hasn't voted to show up at the polls tomorrow," said James Bernsen, a spokesman for Cruz.

Dewhurst was the frontrunner-with Cruz not too far behind- heading into the state's May primary, but the lieutenant governor failed to cross the 50% threshold needed to clinch the nomination, forcing the race into a runoff.

The Texas summer simmered with the heated contest held to replace retiring Sen. Kay Bailey Hutchison. The race quickly turned negative, with both campaigns releasing a steady stream of attack ads and the two candidates exchanging jabs in a fiery debate last month.

Cruz's campaign touts high-profile endorsements, a few of whom recently showed up for the candidate in the Lone Star State. Former Alaska Gov. Sarah Palin, South Carolina Sen. Jim DeMint, and 2012 GOP presidential contender Rick Santorum all headlined events for Cruz this weekend.

At a Houston rally on Friday, Palin and DeMint especially fired up the crowd with anti-establishment, anti-Washington undertones, similar refrains from those heard during the midterm elections two years ago.

"2010 was just a step in that long march towards the real reform that we need," Palin said. "Texas will you keep fighting? Will you keep marching for the real reform that we need in Washington?"

While Dewhurst has spent more than three times the amount of his opponent this cycle, Cruz has been bolstered by millions in outside spending from national groups like FreedomWorks, Club for Growth and Senate Conservatives Fund.

Dewhurst's campaign, meanwhile, highlights his support from local conservative leaders and organizations, not national groups. In a television ad released mid July, Dewhurst's team capitalized on anti-D.C. fever and turned it back against his opponent.

"(Cruz) is a lawyer trained in Washington. Half the money supporting Cruz comes from Washington," the ad's narrator said, later adding: "Lawyer Ted Cruz in corrupt Washington? He'd fit right in."

Gov. Perry has also been vocal in defending Dewhurst. Some political analysts view the race as a referendum on Perry, who critics accuse of lacking conservative credentials–a noteworthy twist given that the Texas governor entered the 2012 presidential race last year under the guise of being the more conservative option over Mitt Romney.

Whoever wins Tuesday's contest will likely win the Senate seat in November. Political handicappers Charlie Cook and Stuart Rothenberg both rate the reliably red state as safe for Republicans.