Cornyn's campaign declined to respond to the poll.

But Republican Party of Texas spokesman Hans Klingler said what the survey does not capture is the opinion of Texans when they compare Cornyn's conservative record to "liberal" votes Noriega has cast as a state legislator from Houston.

"Once his (Noriega's) message gets out statewide, it's good for Cornyn," Klingler said.

The survey by Lake Research of 500 Texans likely to vote in next year's general election found 41 percent disapproved of the job Cornyn has done in the Senate, while 36 percent rate Cornyn as excellent or good.

But only 31 percent of those surveyed said they definitely would vote for Cornyn's re-election. More than half, 53 percent, said they would consider someone else for the Senate. The margin of error for the poll, conducted Nov. 13-18, was 4.4 percentage points.

Cornyn, whose first-term tenure has been marked by his open support for the Bush administration, also may be hampered by his ties to the president.

The Lake poll found 53 percent of Texans disapproved of Bush's performance in office, with 44 percent having a favorable view. That is consistent with a Survey USA poll conducted in June that found Bush was rated poorly by 57 percent of the Texans surveyed.

Pollster Celinda Lake, in a memo written for Noriega's campaign, also noted that a Texas Lyceum poll released in June showed 62 percent of Texans believe the nation is on the wrong track.

"In sum, Senator Cornyn has a weak public profile that is vulnerable to further negative definition," Lake wrote. "He has a small base of political support, and he cannot count on help from a weakened president."

Klingler said Bush's numbers should be improving over the next year because he is not running for re-election, the surge of troops appears to be working in Iraq and the president is fighting Democrats over federal spending. Klingler said the Republicans will have a new political posture.

"That he (Bush) is not on the ballot, Republicans will be looking for other standard-bearers, and John Cornyn is one of them," Klingler said.

Noriega consultant James Aldrete said the campaign commissioned the poll to show donors that Cornyn is vulnerable.

"Clearly, part of it is to show donors the volatility of the race," Aldrete said. "Right now, people might not be firmly with Rick, but they are firmly in the belief that we're on the wrong track."

When Noriega filed for Senate last week, he admitted that he did not have large statewide name identification.

Aldrete said that Cornyn should be bothered by the fact that 38 percent of the voters surveyed have either never heard of Cornyn or don't know enough about him to have an opinion of him.

r.g.ratcliffe@chron.com