DALLAS (CBSDFW.COM) – The final hours before the Republican primary has establishment conservative Lt. Governor David Dewhurst battling it out against Tea Party conservative and former State Solicitor General Ted Cruz for the right to run on the GOP‘s November ticket for U.S. Senate.

Cruz is hoping support from the Tea Party Express will drive him into a runoff with Dewhurst. “This is a major test for the Tea Party. This is a test for the proposition can the establishment write an enormous check, can the lobbyists pour so much money behind David Dewhurst that he buys the race? I don’t think he can,” he told reporters Monday in Richardson.

READ MORE: Pfizer COVID-19 Vaccine Booster Shots Now Available To Older And At-Risk Americans

Dewhurst says those from outside Texas are trying to buy the race for Cruz.

When asked about the Tea Party vs. Establishment dynamic in the race, Dewhurst said he’s been a Tea Partier all along. “I’ve been a Tea Party believer since before the Tea Party was formed when you look at the tenets and the principles of the Tea Party, that the federal government spends too much money, that we need to cut spending, we need to cut taxes.”

Political analyst John Weekley says because Dewhurst is regarded as a conservative, and because Texas has fared better economically than most other states, it will be an uphill battle to beat Dewhurst.   “David Dewhurst has been in the Lt. Governor’s position for so long that he might as well be an incumbent. Statewide name I.D. He’s been in government for a long time.  He hasn’t done anything terribly wrong that upsets a lot of voters.”

Dewhurst is trying to avoid a runoff by spending millions of dollars of his own money to run negative ads against Cruz and former Dallas Mayor Tom Leppert.

READ MORE: 'North Texas Giving Day' Raises A Record-Breaking $66 Million+

If there is a runoff between Dewhurst and Cruz, both Weekley and Collin County Republican Party chairman Fred Moses say Tea Party members could make a difference because they are very active in politics.

“They’ve been more committed to their candidates, and if they’re committed to their candidates, then they will go out to the polls.” says Moses.  But, he adds, it’s too early to discount Leppert, who has strong support in North Texas.

Meanwhile, Democrats also have a primary in the senate race.  Former state representative Paul Sadler is competing against Sean Hubbard, a political newcomer.  But Republicans are considered heavy favorites to retain the seat being vacated by Senator Kay Bailey Hutchinson.

The latest polls show Dewhurst leading Cruz anywhere from 9 to 17 points.  Leppert is in third place, and former broadcaster Craig James in fourth.

MORE NEWS: Texas Secretary Of State's Office Announces Full Forensic Audit Of 2020 General Election in Four Texas Counties

The key question remains, will there be a run-off?  Those same polls show it’s very likely.