Texas is hosting the latest installment in the ongoing saga of Tea Party-backed insurgents taking on establishment Republicans, with former state Solicitor General Ted Cruz looking to overtake Lt. Governor David Dewhurst in the Republican Senate primary.

Polls indicate that Cruz has opened a slight lead over Dewhurst, continuing a surge into contention that began when Dewhurst failed in a May primary to secure the majority of votes needed avoid the looming runoff. The winner of today's primary will have all but secured his path to the Senate, given Texas' reputation as a bedrock Republican state.  

A recent poll from the firm Public Policy Polling gives Cruz a substantial 52-42 lead over Dewhurst. It also confirms that Cruz is the preferred candidate for voters that identify themselves as part of the Tea Party, a bloc that supports Cruz by a yawning 75 to 22 margin.

The race echoes a recurring dynamic of conservative outsiders seeking to upset candidates anointed by the Republican mainstream. But there is a twist: Texas Gov. Rick Perry, a conservative stalwart who was enthusiastically supported by Tea Party-affiliated voters during his unsuccessful presidential run, has been campaigning heavily for Dewhurst.

In addition to winning endorsements from state elected officials, Cruz has also won the backing of former Arkanas governor and presidential candidate Mike Huckabee, another Tea Party favorite who wields considerable clout in the world of conservative opinion-shaping.

But other Tea Party-aligned elected officials have lined up behind Cruz, arguing that he is better positioned to press a conservative agenda and cut down on wasteful spending in Washington. Among them are former Alaska governor Sarah Palin, former Pennsylvania senator and presidential candidate Rick Santorum and South Carolina Sen. Lindsey Graham, the Tea Party's most prominent Senate ally.

In a now-familiar development, outside money has poured into the race, buoying Cruz's prospects. An analysis by the Center for Responsive Politics found that third-party groups have lavished $7.7 on Cruz and $6.2 million on Dewhurst so far, helping to erase the Dewhurst's incumbent advantage.

Some of the groups backing Cruz, like the Club for Growth and the Tea Party Super PAC FreedomWorks, also helped to fund Richard Mourdock's upset victory over Indiana senator Dick Lugar during a May primary. Mourdock successfully called into question Lugar's conservative credentials, a tactic Cruz has employed against Dewhurst.

Scheduling has helped Cruz. A protracted dispute over Texas' redistricting maps led a federal judge postponed the primary, giving Cruz extra time to campaign and introduce himself to voters. The primary was originally scheduled for early March, and by the time May 29 arrived Dewhurst could muster only 45 percent of the vote.