By Maria Caspani
(Reuters) - Republican U.S. senators hold growing leads in key races in Texas and Nevada, a Reuters opinion poll showed, dampening Democratic hopes of taking a majority in that chamber in next month's congressional elections.
The Reuters/Ipsos/UVA Center for Politics poll released Wednesday showed a Democratic incumbent senator broadening her lead in Wisconsin, with the same parties leading competitive governors' races in all three states.
The results follow a major victory for President Donald Trump's Republican Party this month when the Senate confirmed his second Supreme Court nominee, cementing a conservative majority.
The poll showed Republican U.S. Senator Ted Cruz holding the support of 49 percent of likely Texas voters, well ahead of the 44 percent supporting Democratic U.S. Representative Beto O'Rourke. A September version of the poll had shown the two essentially even.
"There's a structural advantage for Cruz that is amounting to five or six points," said Larry Sabato, a University of Virginia political scientist, in a telephone interview. "This is not a purple state, this is a blood-red state."
Democrats face steep odds in trying to capture a Senate majority in the Nov. 6 elections as they have to defend seats in 10 states that Trump won in the 2016 presidential election. Texas and Nevada are among the most competitive Senate races.
"It's a process of the Republicans getting excited and moving into the electorate," said Sabato.
In Nevada, Republican Senator Dean Heller widened his lead over Democratic U.S. Representative Jacky Rosen, with the incumbent Republican holding 47 percent support and 41 percent of respondents backing his Democratic challenger. That is wider than Heller's 3 percentage-point lead last month.
Heller is the only Republican senator defending a seat in a state that Democratic presidential nominee Hillary Clinton won in 2016.
The Reuters/Ipsos/UVA poll was conducted online, in English, from Oct. 12 to 18. It surveyed at least 1,137 people in each state.
The poll results measured how voters felt at the time of the survey. Those feelings may change: In 2016, one in eight Americans said they made their presidential pick in the week before Election Day, according to a Reuters/Ipsos poll.
To see poll results: https://tmsnrt.rs/2piev5l
WISCONSIN HOLDS DEMOCRATIC HOPES
Democrats were better positioned in Wisconsin, where incumbent Democratic U.S. Senator Tammy Baldwin held the support of 54 percent of likely voters, ahead of the 39 percent who backed her opponent Leah Vukmir, a Republican who is closely aligned with Trump.
Trump won Wisconsin by a slim margin in 2016.
Wisconsin Governor Scott Walker, a former Republican presidential candidate who became popular in conservative circles for taking on unions, is locked in a tight race for governor against challenger Tony Evers.
Evers, a schools superintendent in the state, holds a 3 percentage-point lead over Walker, down from the 7 percentage-point advantage Evans held in a separate Reuters poll released in September.
The Democrat's advantage is just outside the poll's 2.5 credibility interval, a measure of precision.
"Scott Walker is a phenomenon in Wisconsin, he never wins by much but he always wins," said Sabato. "This was destined to be a very close race and that's exactly what it is."
The poll showed Republican candidates for governor in both Texas and Nevada ahead of their Democratic opponents.
Some 53 percent of likely Texas voters said they would support the re-election bid of Republican Governor Greg Abbott, compared to 38 percent who supported Lupe Valdez, the Latina former sheriff of Dallas County.
In Nevada, Republican gubernatorial candidate Adam Laxalt had the support of 46 percent of likely voters, while his Democratic opponent Steve Sisolak polled at 41 percent.
For all Reuters election coverage, click: https://www.reuters.com/politics/election2018
(Reporting by Maria Caspani; Editing by Scott Malone and James Dalgleish)