Sean Parnell, the candidate endorsed by former President Donald Trump for U.S. Senate in Pennsylvania, on Monday suspended his campaign after he lost a court fight over custody of his three children in which the judge said he believed allegations of abuse by Parnell's estranged wife.Parnell suspends Senate campaign: Watch the breaking news report in the video player above.In a statement, Sean Parnell said he was devastated by the judge's decision, and planned to ask the judge to reconsider, but that he cannot continue his campaign.The high-stakes campaign in the battleground state could help determine control of the U.S. Senate in next year's election.The decision by a judge in Butler County came two weeks after Parnell took the stand to deny allegations by his estranged wife that he had hurt her and the children.The judge, James Arner, wrote in an order Monday that Parnell's estranged wife, Laurie Snell, will have sole legal custody of the school-age children, as well as primary physical custody. Parnell will have physical custody on three weekends per month, Arner wrote.Snell was "the more credible witness," Arner summed up in his 16-page opinion, saying she could remember and describe details in a convincing manner.More: Parnell's wife questioned in custody casePennsylvania's Senate seat is opening up with the retirement of two-term Republican Sen. Pat Toomey, and both Republicans and Democrats have a big field of candidates in the politically divided state.Parnell's withdrawal comes as many in the state Republican Party remain undecided about their field, which includes conservative commentator Kathy Barnette, real estate investor Jeff Bartos and Carla Sands, Trump's ambassador to Denmark.Also swirling is a suggestion from Mehmet Oz - the cardiac surgeon and longtime host of TV's "Dr. Oz Show" who gained fame as a protege of Oprah Winfrey - that he is being encouraged to enter the Republican primary.Parnell's withdrawal represents a major blow to Trump, who had enthusiastically endorsed Parnell in September with the encouragement of his eldest son.Trump spokesperson Taylor Budowich said Trump and Parnell spoke before Parnell’s announcement and that Parnell informed Trump of his intention to suspend his campaign, given the decision.He said on Twitter that the Pennsylvania Senate race “remains a top priority” for the former president and that “rallying our movement behind the best America 1st candidate remains critical.”Parnell's candidacy was a constant presence in the case, with the judge noting in his opinion that Parnell argued that Snell "is motivated to embarrass him in public and damage his political career," while Snell argued that Parnell "is motivated to preserve a public image and his political career."Snell testified about enduring years of rage and abuse from Parnell, including once when he choked her so hard she had to bite him to get free and another time when he slapped one of their children hard enough to leave welts through the back of the child's shirt.Parnell's testimony, rather, he found "less credible," saying Parnell was "somewhat evasive" and simply denied Snell's allegations."Upon consideration of the credible evidence, I find that Sean Parnell did commit some acts of abuse in the past" against Snell, Arner wrote. He also believed that Parnell slapped the child, as Snell testified, Arner wrote.But, he wrote, Snell having agreed previously that Parnell can have substantial periods of unsupervised custody indicates that she does not view him as posing harm to the children, Arner wrote.Snell's lawyer, Jen Gilliland Vanasdale, said Snell "is grateful that justice prevailed."Testifying under oath on Nov. 8, Parnell denied Snell's allegations, saying he had never choked her or pinned her down, and never struck one of their children in a fit of rage.Snell and Parnell have been living apart for at least three years, but had split custody of their children evenly.Parnell’s history with his wife became a subject in the Republican primary campaign, days after Trump's endorsement.Parnell, a decorated former Army Ranger who led a platoon in Afghanistan, penned a memoir of his service, which became a New York Times bestseller. He also has written four action novels, and emerged as a regular guest on Fox News programs before running for Congress last year and landing a coveted speaking slot at the Republican National Convention.Trump's endorsement came in early September, as Parnell was an in-demand guest on cable TV and conservative podcasts to discuss the Taliban's seizing control of Afghanistan ahead of the withdrawal of American forces.Even amid headlines about the custody case, Trump had backed up his support for Parnell by scheduling a fundraiser with Donald Trump Jr. on Jan. 25 at Trump’s Mar-a-Lago Club in Palm Beach, Florida.Trump allies have privately warned that his haphazard endorsement process — often driven more by a thirst for revenge or flattery than strategic considerations about who is best positioned to win a general election — could create headaches for him down the line.Trump takes great pride in his endorsement record, seeing it as a proxy of his political strength, and some aides have counseled him to be more judicious in his picks.In addition to Parnell, Trump has endorsed several other candidates who have faced allegations of assaulting women, including former White House staffer Max Miller. Miller has denied the charges.___Associated Press writer Jill Colvin in New York contributed to this report.(Copyright 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.)Pennsylvania Democratic Party spokesperson Jack Doyle released a statement after Parnell dropped out of the race: “Today’s developments will only throw Pennsylvania’s Republican Senate primary into further chaos. The vicious infighting amongst the GOP Senate candidates in this race is sure to intensify, and by the time this GOP primary is over voters will have seen why no Republican candidate can be trusted to represent Pennsylvania in the Senate.”