Updated: 3/28, 7 p.m.

LOS ANGELES (CBSDFW.COM/AP) – Former President George H.W. Bush will endorse Mitt Romney at an event Thursday in Houston. Romney spokeswoman Gail Gitcho says the two will appear together to speak to reporters.

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Formal backing from the 41st president is another sign that the Republican Party is uniting behind Romney, as pressure builds on challengers Rick Santorum and Newt Gingrich to leave the race.

“That tells other people, not just in Texas but others in the party and Bush fans, that he’s OK,” said Dallas-based political analyst John Weekley. “President Bush appeals not just to moderates by a lot of conservatives.”

The elder Bush has offered encouraging words to Romney throughout the primary season, but had withheld a formal endorsement.

Former first lady Barbara Bush has formally backed Romney. She recorded automated telephone calls for him during the primary in Ohio. Their son, former Florida Governor Jeb Bush, endorsed Romney last week, telling students at the University of Texas at Arlington that he felt Romney was the most able Republican to defeat President Barack Obama.

“I think he’s the candidate who can beat President Obama. I think he will be a fine President and I think he’s going to win the Republican nomination,” Gov. Bush told attendees during the UTA event.

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Messages left at the Dallas office of former President George W. Bush requesting comment on whether he will also endorse Romney went unreturned Wednesday.

Weekley says that while the former President is admired by Republicans, he may be cautious about an endorsement considering who the incumbent is.

“He’s often the foil for President Obama anytme anything goes wrong, the first one off the freeway is President Bush, it’s his fault, it happened under his watch, and I think President Bush is sensitive to that,” he said.

Romney is scheduled to appear at a private fundraiser in Dallas on Wednesday evening. Invited supporters will be able to snap photographs with the former Massachusettes governor at 5:30 p.m. at the Fairmont Hotel downtown, prior to a 6:00 p.m. dinner.

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)

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