WASHINGTON — A new Texas poll shows President Donald Trump losing 48-44 to former Vice President Joe Biden.

The Quinnipiac University Poll, released Wednesday afternoon, shows Trump edging past other Democratic contenders, including Texans Beto O'Rourke and Julian Castro.

"Biden ... dominates the field in a Democratic primary and has the best showing in a head-to-head match-up against President Donald Trump," said Peter A. Brown, assistant director of the Quinnipiac poll. But he added, "In historically red-leaning Texas, the report for the rest of the Democratic field is not so bad either, which could spell trouble for President Trump."

Trump fares "barely" any better against other Democratic contenders, Brown noted:

 Against Massachusetts Sen. Elizabeth Warren, Trump leads 46-45.

 Against Vermont Sen. Bernie Sanders, Trump leads 47-44.

 Against O'Rourke, Trump leads 48-45.

 Against South Bend Mayor Pete Buttigieg, Trump leads 46-44.

 Against California Sen. Kamala Harris, Trump leads 47-43.

 Against Castro, the former San Antonio mayor and federal housing secretary, Trump leads 46-43.

The survey, conducted May 29 to June 4, has a margin of error of 3.4 percentage points in either direction. So all of those contenders are within statistical dead heat range of the president.

Is GOP grip on Texas slipping?

Democrats dominate California and New York. If they could nab Texas' electoral votes, Republicans would find it all but impossible to win the White House. Trump carried Texas by just 9 percentage points over Hillary Clinton in 2016. That was the GOP's worst showing in decades and, for strategists in both parties, a sign that the party's grip on Texas was slipping.

"Poll after poll shows the same result: Texas is the biggest battleground state and the focal point of the Democratic offensive strategy," said Texas Democratic Party executive director Manny Garcia. "This is our moment. We all know that once Texas goes blue, the Republican path to the White House will be blocked."

Quinnipiac also surveyed Texas Democrats to assess their preference for nominee.

Biden topped the field with 30%, followed by O'Rourke at 16%, Sanders at 15%, Warren at 11%, Castro and Harris tied at 4%, and Buttigieg at 3%. No other candidate broke 2%.

Should O'Rourke challenge Cornyn?

By more than 2-to-1, Texas Democrats said they'd prefer to see O'Rourke run against Sen. John Cornyn rather than continue his bid for president.

O'Rourke held Sen. Ted Cruz below 51% last fall and collected more votes than any Democrat ever to appear on a Texas ballot, including presidential nominees. M.J. Hegar, a former military pilot who narrowly lost a bid last fall against Rep. John Carter, R-Round Rock, is the most prominent Democrat angling for a shot at Cornyn; Quinnipiac didn't ask any questions about her.

The latest Quinnipiac survey supports Biden's contention that he would be the most formidable challenger to Trump. The same pollsters three months ago found that in Texas, Trump led Biden 47-46.

Against other contenders, Trump's edge in Texas hasn't changed much. In late February, he topped Sanders 47-45 and edged past O'Rourke 47-46.

An Emerson College poll conducted April 25-28 showed Biden and O'Rourke in a dead heat among Democratic voters in Texas, with Biden the top choice of 23% and O'Rourke at 22%.

That poll also tested potential head-to-head match-ups in Texas against Trump. Again, Biden and O'Rourke tested best among the Democratic contenders, with Biden ahead 50%-49% and O'Rourke even with Trump at 50%.

The former vice president officially entered the race on April 25 as the front-runner, and his lead has grown since then. Nearly all candidates enjoy a bounce in the days and weeks after they launch their campaigns. Biden's was far bigger than most and has only recently shown signs of easing.