US President Donald Trump in Singapore. Credit:AP Trump's grip on the party will have consequences in the 2018 campaign for control of Congress, which will determine whether he's able to forge ahead with his agenda. While it may only enhance the prospects of candidates like Arrington running in safely Republican areas, dozens of other GOP candidates in swing districts will be facing Democrats trying to capitalise on intense voter polarisation generated by Trump with a promise to serve as a counterweight. Trump's quick Twitter finger and his habit of launching highly personal attacks against lawmakers of either party has only enhanced his stature among his core supporters. That's made Republicans in Congress wary of speaking out, even when the President goes against long-held party positions on issues such as trade. From left, Matthew Sakowski, Dylan King, Evan Sakowski and Bryce King spell out the letters "TRUMP" as they wait with other supporters to watch a Trump rally in Washington. Credit:AP "We're in a strange place. I mean it's almost becoming a cultish thing," Senator Bob Corker, a retiring Tennessee Republican, told reporters on Wednesday, a day after lambasting other GOP lawmakers on the floor of the Senate for being too afraid of Trump to rein in his authority to impose tariffs.

"It's not a good place for any party to end up with a cult-like situation as it relates to a President that happens to be of, purportedly, the same party," Corker said. Sanford found out just how tight the grip is. A solidly conservative Republican who regularly won elections in the state and usually votes with Trump, his main heresy was in faulting the President for coarsening the national discourse with his bombastic and insulting rhetoric. During the campaign, Arrington ran an ad in which she vowed to go to Washington to "get things done, not to go on CNN to bash President Trump." Republican primary senatorial candidate Corey Stewart, right, gestures as state Delegate Nick Freitas listens during a debate at Liberty University in Lynchburg, Virginia. Credit:AP Just three hours before polls closed on Tuesday, Trump unloaded on Sanford in a tweet labelling him "nothing but trouble" and endorsing Arrington. In unofficial results, Arrington won with 50.6 per cent of the vote to Sanford's 46.5 per cent. In his concession, Sanford, the state's former governor, said, "It may have cost me an election in this case, but I stand by every one of those decisions to disagree with the President."

Sanford is the second House Republican on the wrong side of Trump to land in hot water during the GOP primaries. Alabama's Martha Roby was forced to a run-off. She said in 2016 she couldn't support Trump for president after tape emerged of him boasting in 2005 about groping women's genitals. Trump took a victory lap on Wednesday, saying on Twitter that he was urged by advisers not to get involved in the primary, but "Sanford was so bad, I had to give it a shot". The defeat seemed to surprise Sanford - he had $US1.6 million ($2.2 million) in campaign funds sitting in the bank by May 23, according to a recent Federal Election Commission filing, and ran just $US187,700 worth of ads in the district's top two media markets. Now Sanford will join Corker and Arizona Senator Jeff Flake, another Republican Trump critic, in retirement. Corker and Flake both decided not to seek re-election. They likely will be replaced with Trump loyalists as the Republican candidates in their states on the November ballot. In both cases, the races for what once were relatively secure Republican seats now are rated as toss-ups by the non-partisan Cook Political Report. The cult of President Donald Trump. Credit:AP In Virginia on Tuesday, Republicans nominated as their US Senate candidate Corey Stewart, who brought Trump-style brashness and a promise of a "vicious" campaign to his race against a more moderate challenger backed by the state Republican Party.

Stewart, a county supervisor, has championed Confederate monuments and accepted the endorsement of a neo-Confederate leader. Last year, he defended white nationalist rally-goers in Charlottesville as only part of the problem in the violent march. He'll face incumbent Democratic Senator Tim Kaine, who was Hillary Clinton's running mate in the 2016 presidential campaign. Kaine is the heavy favourite in November. Brian Walsh, a lobbyist and former aide for the Senate GOP campaign arm, tweeted shortly after the primary that Kaine "won his re-election tonight," urging voters to skip past "all the idiotic, racist & embarrassing things Corey Stewart will say & do the next five months." A Trump supporter at a rally in Florida in January. Credit:AP Trump, though, was enthusiastic.

"Congratulations to Corey Stewart for his great victory for Senator from Virginia," the President tweeted on Wednesday. "Don't underestimate Corey, a major chance of winning!" Also on Tuesday, House Republican leaders averted a rebellion by moderates seeking to end-run Speaker Paul Ryan and force votes on legislation opposed by Trump that would give young undocumented immigrants a path to citizenship. The move buys House leaders time to negotiate a bill that includes more of Trump's requests for border security and enforcement. Republican lawmakers will face another test in defying Trump on trade this week as they are joined by Democrats in an attempt to block the administration's deal with the Chinese telecommunications company ZTE. The bipartisan opposition is holding so far, but the administration is pressing to dial back the proposal. Trump has thrown his support behind a Virginian Republican who defended the white nationalist rally in Charlottesville, Virginia in 2017. Credit:AP "We think we can fix it" when the House and Senate are negotiating differences in their separate bill, said Marc Short, the White House legislative affairs director.

Former House Speaker John Boehner said last month he no longer recognises his party. "There is no Republican party. There is a Trump party," the Ohio Republican, who retired in 2015, said on May 31 at the Mackinac Policy Conference in Michigan. "The Republican Party is kind of taking a nap somewhere." Bloomberg