Senate Republican leader Mitch McConnell leaves the floor of the Senate on Tuesday. Senate Republicans voted overwhelmingly on Jan 26 against moving forward with Donald Trump's historic second impeachment trial. (SAMUEL CORUM/GETTY IMAGES/AGENCE FRANCE-PRESSE)

NEW YORK - The Democrats' efforts to convict Donald Trump at his impeachment trial suffered a fresh blow on Tuesday when almost all Republican senators backed dismissing the case, underlining the former US president's continuing hold over the party.

The US Senate voted 55-45 to go ahead with Trump's second impeachment trial, but only five Republican senators voted with Democrats.

But the result confirmed Democrats will struggle to persuade 17 Republican senators－the number needed for the required two-thirds majority－to vote to convict Trump.

The US House of Representatives on Monday presented a single article of impeachment to the upper chamber accusing Trump of inciting the storming of the Capitol earlier this month, setting in motion the first impeachment trial of a former president in the country's history

Republican Senator Rand Paul raised a point of order to hold a vote on the constitutionality of the impeachment trial as Trump has left office.

Democrats then called for a vote to kill the point of order, winning 55-45.

Paul said afterward: "Forty-five Senators agreed that this sham of a 'trial' is unconstitutional. ... This 'trial' is dead on arrival in the Senate.

"We're excited about it. It was one of the few times in Washington where a loss is actually a victory," he said.

Two-thirds of the Senate, or 67 senators, must vote to convict Trump. If convicted, a separate majority vote in the Senate will decide on possible punishments which include Trump being barred from holding federal office in the future. Trump is reportedly considering running for president again in 2024.

Patrick Leahy, the 80-year-old senator presiding over the trial, was briefly hospitalized after Tuesday's proceedings during which he sounded hoarse and unwell as lawmakers were sworn in as jurors.

"The Attending Physician recommended that he be taken to a hospital for observation," his spokesman said. Leahy was released later in the evening.

Leahy, who was elected in 1974, is presiding as he is the senior senator of the party with the majority in the Senate, currently the Democrats.

The US House of Representatives on Monday presented a single article of impeachment to the upper chamber accusing Trump of inciting the storming of the Capitol earlier this month, setting in motion the first impeachment trial of a former president in the country's history.

ALSO READ: US House to deliver Trump impeachment to Senate Monday

The trial of Trump, who was impeached by the Democratic-majority House for an unprecedented second time, is to begin the week starting on Feb 8.

Political muscle

Trump－winner of 74 million votes in his loss to Biden on Nov 3 and reportedly sitting on nearly $70 million in campaign funds－wants Republican senators to consider their own futures before they dare cross him, news agency Agence France-Presse said.

Trump's main way of applying pressure while out of office is to threaten disloyal legislators with support for their challengers in party primary votes ahead of the 2022 midterm elections.

READ MORE: Trump impeachment trial opens as watchdog says he broke law

Trump's endorsement on Monday of his former White House press secretary Sarah Sanders in her bid to become governor of Arkansas was a first flexing of this political muscle.