O'Rourke, Castro running even with Cruz, poll shows The statewide survey by Texas Lyceum shows the incumbent Republican U.S. senator vulnerable heading into 2018 while President Trump's approval rating lags in the nation's largest red state.

John C. Moritz | USA Today Network Austin Bureau

Show Caption Hide Caption Everything There is to Know About Beto O'Rourke Congressman Beto O'Rourke is challenging Senator Ted Cruz for Senate. Here is what you need to know about him.

AUSTIN – Either of the two Democratic congressmen who could end up with the 2018 nomination for the U.S. Senate would give Republican incumbent Ted Cruz a run for his money in the nation’s largest and perhaps most reliably red state, a poll released Tuesday shows.

The survey of 1,000 adult Texans also shows Republican Lt. Gov. Dan Patrick’s would-be Democratic challenger just a few points behind, though both potentially high-profile statewide matchups showed that a lot of people are not yet thinking about the upcoming election cycle.

“Ballot tests conducted this far in advance of an actual election are, at best, useful in gauging the potential weaknesses of incumbents seeking re-election,” said Daron Shaw, the polling director for the nonprofit leadership development group, Texas Lyceum. “But the substantial percentage of undecided respondents — coupled with the conservative, pro-Republican proclivities of the Texas electorate in recent years — suggest a cautious interpretation.”

The poll, which carries a 3.1-percentage-point margin of error, sampled Texans over 18 but did not screen respondents to determine if they were likely to vote next year, or even if they were registered to vote. Had they included only likely voters, the sample probably would have contained more respondents who lean Republican, said Joshua Blank, also a Lyceum pollster.

The tepid enthusiasm for Cruz, a first-term senator who made a failed bid for the Republican presidential nomination, and for Patrick, also in his first term and tightly aligned with the GOP’s conservative wing, could be tied to the low standing of President Donald Trump among Texans.

Related: O'Rourke will challenge Cruz for Senate in 2018

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The president, who won the White House in an upset last year but carried Texas by a comfortable margin, was upside down in his rating with 54 percent of the respondents disapproving of his performance in office so far. Only 42 percent said he’s doing a good job as he approached the 100-day mark in his presidency.

However, among Republican respondents, 85 percent gave Trump high marks. Democrats offered a near mirror image with 86 percent saying his presidency is off to a poor start.

Cruz is looking at a challenge from either Congressman Beto O’Rourke of El Paso, who declared his candidacy last month, or from San Antonio Congressman Joaquin Castro, who is mulling a run.

In the Lyceum Poll, the better-known Castro outpaces the Republican 35 percent to 31 percent with the balance either undecided or not even thinking about a race that won’t be held until November of next year. O’Rourke would tie Cruz 30-30.

U.S. Rep. Joaquín Castro hosts rally in El Paso U.S. Rep. Joaquín Castro talks Saturday during an evening rally in El Paso.

Patrick, a former talk radio host and state senator from Houston, trails Democrat Mike Collier, an accountant who was soundly beaten in the race for state comptroller in 2014, 27 percent to 25. But nearly half of the respondents said the lieutenant governor’s race is not yet on their minds.

Republican Gov. Greg Abbott, who has no announced challenger for 2018, has an approval rating of 53 percent.

Brandon Rottinghaus, a University of Houston political science professor, said even though the results are likely skewed because the sample was not limited only to likely voters, the long out-of-power Texas Democrats could take some comfort in the fact that two well-known Republicans showed such soft support.

"That's a narrative the Democrats will like to read and it's a narrative they'll like to push, even though it may not be true," Rottinghaus said.

Related: Potenial Cruz foes to visit each others’ turf

Castro talks national issues while mulling Senate bid

True or not, soon after the poll's results were released, the head of Texas Democrats used the findings as a tool to raise money for the party that hasn't won a statewide election since 1994 and is badly outnumbered in both houses of the Legislature.

"We must have the resources to keep building a stronger state party, hire more staff to organize, support our candidates, and provide support to our county parties," state Democratic Chairman Gilberto Hinojosa said in an email blast. "We have a once-in-a-life opportunity to beat Trump Republicans."

But one veteran Republican strategist called that optimistic message another in a long string of futile efforts by Texas Democrats to see victory around the next bend.

"Every election cycle for the past 20 years, the Democrats have said, 'This is the year we are poised to win.' And every cycle, they never do, and their not going to (this cycle) either," said Ray Sullivan, who worked on campaigns for such high-profile Texas Republicans as George W. Bush and Rick Perry.

"Sure, in 2018, Republicans are going to have to run hard," he added, noting that off-year elections tend to favor the party that's not in the White House. "But the Republicans have a huge organizational advantage in Texas and a huge monetary advantage."

John C. Moritz covers Texas government and politics for the USA Today Network in Austin. Contact him at John.Moritz@caller.com and follow him on Twitter @JohnnieMo.