The No.2 Republican in the Senate is polling below the 50 percent threshold in the party’s March 4 primary that he needs to clear in order to avoid a May 10 runoff, according to a Feb. 10-12 Human Events/Gravis poll of 729 registered Republicans.

Sen. John Cornyn (R.-Texas), the GOP Whip in the upper chamber has the approval 49 percent of those questioned and 43 percent preferred him to main challenger Rep. Stephen E. Stockman (R.-Texas), who polled 28 percent, said Doug Kaplan, the president of Gravis Marketing, the Florida-based firm that conducted the poll with both live callers to cell phones and automated calls to landlines. The poll has a margin of error of 3.6 percent.

Twenty-nine percent of respondents were unsure, he said.

“These are dangerous numbers for Cornyn, because they show that despite his power in the Senate and his familiarity with the voters, he has not yet made the sale,” he said.

Kaplan said Stockman’s numbers are better than in the Oct. 26 poll Human Events/Gravis poll of Texas GOP registered voters. “In that poll, Stockman polled 15 percent head-to-head with Cornyn.”

In the previous poll, Cornyn lost to a generic Tea Party candidate 46 percent to 33 percent with 46 percent approving of the senator’s job performance, he said. In the same poll, Sen. R. Edward “Ted” Cruz (R-Texas) was approved of by 73 percent.

The Cornyn campaign was given the poll results three days before the deadline and asked for comment for this story. Campaign spokesman Drew Brandwie said the campaign would respond, but no response was received.

The other Republicans on primary ballot are: Chris Mapp, Dwayne Stovall, Linda Vega, Curt Cleaver, Reid Reasor and Ken Cope. A run off would between the top two vote getters.

Stockman said he is energized about the primary fight, but he is distressed by the personal attacks from Cornyn’s campaign and an independent political action committee that shares the 45 North Hill Drive address in Warrenton, Va., with a Karl Rove’s American Crossroads Super PAC.

“The Cornyn campaign must have inside poll numbers that scare them,” the congressman said. “They are throwing everything at me, including things I did 20 years ago, before I became a Christian.”

Donny Ferguson, a spokesman for the Stockman campaign, said “The buzzards are circling around Cornyn’s campaign office. A runoff election is a death sentence for an incumbent.”

Stockman only started his campaign less than 90 days ago and is growing rapidly, he said.

“This is why Cornyn refuses to release his internal poll numbers,” he said.

“The only thing holding Congressman Steve Stockman back is that 55 percent of Republican primary voters aren’t familiar with him,” he said.

“In fact, this poll shows meteoric growth in support for Congressman Steve Stockman, who only started running less than 90 days ago.” Ferguson said, “Also, this poll was taken before voters learned Cornyn voted to raise Obama’s debt limit. That vote created a new, larger explosion of opposition to Cornyn that he’s struggling to contain.”

Professor Sean M. Theriault, who teaches political science the University of Texas at Austin, said, the poll tells more about Cornyn’s problems than Stockman’s success.

“I wouldn’t say that ‘Stockman’ is still hanging around, I would say that ‘Anyone other than Cornyn’ is hanging around,” said the author of the book “Party Polarization in Congress” published in 2008.

“A huge difference between anyone and Stockman is that the more than Texans learn about Stockman, the more popular that Cornyn will become,” the professor said.

“Stockman is not Cruz 2.0. The voters will come back to Cornyn once they focus on the race.”

Clinton Cook, a board member of the Texas Tea Party Alliance, Cornyn has been a disappointment.

“Cornyn is a master, like any politician, of people what they wanted to hear,” he said.

“He tells his supposed base in Texas what they want to hear, but when push comes to shove, he continues to promote policies that promote centralized control from Washington.”

A great example, is when the senator voted to break the filibuster on the vote to raise the debt ceiling, he said. “At the end of the day, he votes how he really feels.”

William C. Fairbrother, who has been the chairman of the Williamson County GOP Committee for 15 years, said Cornyn’s vote to raise the debt ceiling did not make him happy.

“The vote to procedurally allow the debt ceiling measure to pass is one I respectfully disagree with,” he said.

Fairbrother, who works as a technology consultant, said he understands why Republicans would be angry with Cornyn. “But, the case for change has not been made. I have always found him to be a good, contemplative and conservative individual.”

Professor Richard Murray, who teaches political science at the University of Houston, said the poll reflects what his is seeing in the primary campaign. But, because the poll was taken before the senator voted to raise the debt limit, he could be doing worse.

“Cornyn has vulnerabilities, but he will survive because Stockman is essentially running no campaign,” said the director of the Survey Research Institute at the university’s Hobby Center for Public Policy. “He has never been very visible in the state—he does not toot his own horn much.”

Murray said he sees the race as a test of the anti-establishment vote, which he pegged at 30 percent. In the short-term, Cornyn is taking a hit, but it will not be enough to force a run off, he said.

If there was a run off, because it is held in May there would be time for Stockman to ramp up a more active campaign and beat Cornyn, he said. “Cornyn really needs to win this primary on the fourth of March.”