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.
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.
Haspel, whose Senate confirmation hearing is next month, also faces a tough confirmation fight. "He has invigorated the Central Intelligence Agency clandestine service, tried to give Mr. Trump options on North Korea, and has gained the President's trust".
With only a slim 51-49 majority in the Senate, Pompeo's nomination hinges on support from Senate Democrats, with many facing pressure to more stridently oppose U.S. President Donald Trump. Unfortunately, many of my colleagues across the aisle are making Pompeo's nomination about politics, instead of his fitness to serve our country as the nation's top diplomat. That changed significantly a year ago when Rex Tillerson's nomination was approved on a largely party-line vote of 56-43 that saw just four Democrats cross the line to vote yes.
Trump recently sent Pompeo to Pyongyang to meet with North Korean ruler Kim Jong Un in advance of Trump's planned summit with Kim to discuss the denuclearization of the Korean peninsula.
One thing I know for sure is that of all the folks involved, I trust Kansan Mike Pompeo. Heidi Heitkamp of North Dakota, who announced her support last week - have committed to back Pompeo's confirmation.
In a briefing Monday afternoon at the White House, Sarah Huckabee Sanders, the White House press secretary, dismissed Democratic opposition as "pointless obstruction to score cheap political points with their base as a willful attempt to undermine American diplomacy".
"As a Kansan, I hold a deep reverence for the sanctity of life, the solidarity of family, and the solemnity of marriage", he said previously.
In a letter to the Senate Foreign Relations Committee, the ADL writes: "Pompeo's past anti-Muslim statements and his associations with organizations that have frequently expressed hostility toward Muslims and trafficked in anti-Muslim conspiracy theories". Cory Booker, of New Jersey, who made headlines during hearings over Pompeo's nomination. It's no mistake that these three Democrats would come in line behind the nomination, of course, given that all three of them are up for reelection in deeply red states that President Trump won by overwhelming margins in 2016 and are considered among some of the most vulnerable Democratic Senators in the country.
Grenell was nominated by President Donald Trump to serve as the next US ambassador to Germany in September 2017, but has languished for months without a Senate vote.