Senator Jeff Sessions, incoming President Donald Trump's pick for Attorney-General, will face a Senate committee next Tuesday, in the first of a series of confirmation hearings in which the opposition Democratic Party has pledged to turn up the heat.
Mr Trump may expect nominees for top positions in his administration to clear their confirmation hearings and be ready to take office by his inauguration on Jan 20, but this may not happen if Democratic Senator Charles Schumer, 66, the new leader of the Democratic Party in the Senate, has his way.
Mr Schumer has sworn that the hearings will be rigorous.
On paper, the Republicans have more than 51 per cent of the Senate, so pushing through their nominees should not be an issue.
There is also a tradition of allowing the incoming president to have a Cabinet filled with all his picks.
Historically, only nine presidential nominees for Cabinet positions have been rejected by the Senate - although a further 12 were withdrawn before coming to a Senate vote.
But given the current rancorous political atmosphere, all eyes will be on the first hearings on Jan 10 and 11, which could set the tone for the early days of the Trump administration.
While the Democrats want a minimum two days of hearings per Cabinet appointee, and no more than two to face hearings in the same week, the Senate's Republican-led committees have already scheduled six hearings on Wednesday alone.
"Any attempt by the Republicans to have a series of rushed, truncated hearings before Inauguration Day, and before the Congress and public have adequate information... is something the Democrats will vehemently resist," Mr Schumer told The Washington Post this week.
"If the Republicans think they can quickly jam through a whole slate of nominees without a fair hearing process, they are sorely mistaken."
The Republicans have said they will pay back the Democrats by debating until the wee hours of the morning. While the Democrats want a minimum of two days of hearings per Cabinet appointee, and no more than two to face hearings in the same week, the Senate's Republican-led committees have already scheduled six hearings on Wednesday alone.
The tussle could mean that some nominees will not be confirmed by Jan 20 and could delay implementation of the Republican agenda.
Ms Rachna Choudhry, co-founder of POPVOX.com, a non-partisan platform that tracks congressional activity, told The Straits Times: "It may come to a standstill in terms of the agenda, but there is a lot an agency does which is apolitical."
"A department will continue to function without a Secretary (of State) leading it," she added.
Mr Trump has generated controversy with some of his appointees.
Beside Senator Sessions, the Democrats' main targets will be the nominees for Secretaries of State, Labour, the Treasury, Health and Human Services, and Education; as well as the head of the Environmental Protection Agency.
But Senator Sessions, 70, may be the most vulnerable, especially as he had failed a confirmation hearing - in 1986 - over allegations of racism.
Earlier this week, more than 1,100 law school professors from 48 states sent a letter to Congress saying they are "convinced that Jeff Sessions will not fairly enforce (the) nation's laws, and promote justice and equality in the United States".
They wrote: "Nothing in Senator Sessions' public life since 1986 has convinced us that he is a different man than the 39-year-old attorney who was deemed too racially insensitive to be a federal district court judge."
The relevant Senate committee votes on the nominee once it has held a hearing. If the committee votes to move the nomination to the next step, the full Senate will then vote. A nominee needs a simple majority for approval. If 51 of the 100 Senators vote in support, then that nominee is confirmed.