WASHINGTON (BLOOMBERG) - Mr Mike Pompeo may fail to win approval from the Senate Foreign Relations Committee to be the next US secretary of state.

It would be an unprecedented slight, but it might not matter.

With Republican Rand Paul and Democrats on the panel opposed to making the CIA director the top US diplomat, the committee may vote narrowly against President Donald Trump's nominee on Monday evening (April 23).

But Republican leaders have vowed to bring the nomination before the full Senate, where Mr Pompeo appears to have enough support to become the 70th secretary of state by the week's end.

Some lawmakers question whether Mr Pompeo, a hardliner who came to Washington as a Tea Party congressman, has the temperament for diplomacy, but he has one significant advantage - Mr Trump's confidence in him.

Unlike his fired predecessor, Mr Rex Tillerson, Mr Pompeo can be expected to convey the President's messages to the world, and he may be able to get Mr Trump to heed sometimes unwelcome messages from other world leaders and lawmakers.

"The most important thing for a secretary of state is to be perceived as speaking for the President," said Dr Jon Alterman, a senior vice-president at the Centre for Strategic and International Studies, who was a State Department official under President George W. Bush.

"This is all about: Do you have the President's trust, and can you demonstrate you have his trust?"

The divisions over Mr Pompeo reflect the conflicts over Mr Trump and his "America First" foreign policy.

"I realise my Democratic friends in many cases feel like that in supporting Pompeo, it's a proxy for support of the Trump administration policies, which many of them abhor," Senate Foreign Relations Chairman Bob Corker of Tennessee, who has often been unsparing in his criticism of the President, said last week.

Mr Colin Powell was confirmed as secretary by unanimous voice vote in 2001, while Mrs Hillary Clinton and Mr John Kerry cleared the Senate by votes of 94-3 and 94-2.

Yet Mr Tillerson was confirmed on a party-line vote of 56-43.

There's just one instance where any Cabinet member has been confirmed after an unfavourable vote in committee - Commerce Secretary Henry Wallace in 1945, according to the Senate Historical Office.

With a razor-thin Republican majority in the Senate and Democrats largely opposed to Mr Pompeo's nomination, the White House has been playing up his readiness for the job, casting him as an already crucial member of Mr Trump's foreign policy circle who sees him most mornings to help deliver the intelligence community's classified daily briefing.

The administration underscored that point with the disclosure last week that Mr Pompeo made a secret trip to North Korea over the Easter weekend to meet the country's leader, Mr Kim Jong Un.

"Nothing could better underscore the importance of getting America's top diplomat in place for such a time as this," White House spokesman Sarah Huckabee Sanders tweeted. "Dems have an opportunity to put politics aside, acknowledge our national security is too important, and confirm Mike Pompeo. Statesmanship."

After Mr Trump announced in a tweet in March that he was firing Mr Tillerson and nominating Mr Pompeo, his chances for confirmation were considered tenuous enough that 45Committee, an advocacy group that backs the President, began running commercials to press wavering Democratic senators in states that voted for Mr Trump to vote for his confirmation.

They include Senators Joe Donnelly of Indiana and Mr Joe Manchin of West Virginia, who haven't yet said how they'll vote.

"Pompeo is a proven national security leader," one such ad says. "Urge Senator Manchin to again vote yes for Mike Pompeo."

As secretary of state, Mr Pompeo, 54, would have some remedial work to do with the Foreign Relations Committee, which oversees the State Department and its budget.

"There's traditionally been a very close partnership between the State Department and the Senate Foreign Relations Committee," Mr Alterman said.

Failing to win the panel's vote of approval "is not a lethal wound, but it's one that leaves a scar", he said.

On the Senate floor, the focus will be on moderate Democrats who say they're keeping an open mind on Mr Pompeo.

Among them are Mr Doug Jones of Alabama and Mr Mark Warner of Virginia, who as the top Democrat on the Senate Intelligence Committee says he has a strong working relationship with Mr Pompeo.

On Thursday, Mr Pompeo drew the support of Senator Heidi Heitkamp of North Dakota, who's on the ballot in November and whose state gave Mr Trump 63 per cent of the vote in 2016.

She said Mr Pompeo convinced her that he's committed to empowering the diplomatic corps and filling key vacancies such as the US ambassador to South Korea.

Late last week, Mr Pompeo was still making the rounds on Capitol Hill, speaking with key senators who still haven't committed, including Mr Warner, Mr Manchin, and Mr Jeff Flake of Arizona, the only Republican on the Foreign Relations Committee who's undecided.

Ultimately, the committee's vote on Mr Pompeo will be "largely irrelevant in the near future", said Mr Brett Schaefer, a senior research fellow at the Heritage Foundation. "In the end, a secretary of state is a secretary of state whether by one vote or 100."