Trump promotes conspiracy theory that Romney is a Democrat ‘secret asset’ after he votes to convict president

Donald Trump has promoted a conspiracy theory that Mitt Romney is a “secret asset” of the Democratic Party just hours after the Republican senator voted to convict the US president in his impeachment trial of abuse of power.

Mr Romney, a former Republican presidential nominee, delivered a damning speech to the Senate, accusing Mr Trump of an “appalling abuse of public trust” in attempting to pressure Ukraine to open investigations into a political rival in exchange for military aid.

Despite Mr Romney contributing to the bipartisan vote to convict Mr Trump, every other Republican senator sided with the president, meaning he was acquitted on the abuse of power charge by 52 votes to 48.

Following the acquittal on Wednesday, Mr Trump tweeted a video in which a voiceover condemns “slick, slippery, stealthy” Mr Romney for trying to “infiltrate” the Trump administration by “posing as a Republican”.

“Now his cover’s blown – exposed by news reports as a Democrat secret asset,” the voiceover falsely claims. There is no evidence Mr Romney is a Democrat.

The footage shows Mr Romney thanking Mr Trump for an endorsement of his successful 2018 Senate campaign in Utah, before going on to show news reports of his 2012 presidential election loss to Barack Obama. It concludes with footage of Mr Trump winning the 2016 presidential election.

Mr Trump later tweeted: “Had failed presidential candidate @MittRomney devoted the same energy and anger to defeating a faltering Barack Obama as he sanctimoniously does to me, he could have won the election.”

Mr Trump previously twice posted a shortened version of the video, which omitted the reference to Mr Romney as a “secret asset”.

The first came after Mr Romney said he was “sickened” by Mr Trump’s conduct outlined in the Mueller report, the second time late last year when the senator expressed concern over a phone call with the Ukrainian president.

Mr Trump’s son, Donald Trump Jr, had earlier called for Mr Romney to be expelled from the Republican Party in a tweet falsely claiming he was switching parties.

“Mitt Romney is forever bitter that he will never be POTUS. He was too weak to beat the Democrats then so he’s joining them now,” he said.

“He’s now officially a member of the resistance & should be expelled from the @GOP.”

During his speech from the Senate floor, Mr Romney at times appeared close to tears as he outlined his reasons for sanctioning the removal of Mr Trump.

He said he would vote to convict the president for the abuse of power charge, but acquit him on an obstruction of Congress charge. In doing so, he became the first senator in US history to vote for the removal of a president of his own party in an impeachment trial.

"The president is guilty of an appalling abuse of public trust," Mr Romney said during the speech, in which he invoked his sense of duty to argue that the Senate vote will be in-turn judged by history and the American people.

"What he did was not perfect," he continued, referencing the president's claims that his actions were flawless. "No, it was a flagrant assault on our electoral rights, our national security, and our fundamental values. Corrupting an election to keep oneself in office is perhaps the most abusive and destructive violation of one's oath of office that I can imagine."