Given a boost by Donald Trump's victory in the November 8 presidential election, Republicans hope to dismantle the Obama administration's healthcare policies as well as environmental and financial industry regulations.
The Republican-led US Congress begins a new session on Tuesday where it will start pursuing President-elect Donald Trump's agenda of tax cuts, repealing Obamacare, and the rollback of financial and environmental regulations.
Since his election on November 8, the Republican president-elect has made clear he wants to move swiftly to enact proposals he outlined during the campaign such as simplifying the tax code, slashing corporate tax rates and repealing and replacing Obama's signature health insurance program – the Affordable Care Act (ACA), also known as Obamacare.
The law aims to provide health insurance to economically disadvantaged people and expand coverage for others.
Republicans have long sought to dismantle Obamacare, insisting it was unworkable and hampered job growth. But they face a dilemma over how to provide health insurance for the 13.8 million people enrolled in Obamacare who could lose their coverage.
People must remember that ObamaCare just doesn't work, and it is not affordable - 116% increases (Arizona). Bill Clinton called it "CRAZY"— Donald J. Trump (@realDonaldTrump) January 3, 2017
Leading Democrats warned on Monday of a fierce battle over Obamacare.
"We're going to fight as hard as ever to protect the ACA," said Representative Steny Hoyer, the House's second-ranking Democrat.
Speaking to reporters, Hoyer and House Democratic leader Nancy Pelosi said they would launch an effort to mobilise grassroots support for Obamacare by explaining how repeal would create a ripple effect hurting a majority of Americans.
The GOP wants to dismantle ACA & consequently increase costs. It's wrong. It will have an major impact on hardworking families & raise taxes— Nancy Pelosi (@NancyPelosi) January 2, 2017
Obama is scheduled to meet on Wednesday with congressional Democrats to discuss strategies for fending off the Republican attacks on the law.
Battle ahead over Trump nominations
The Senate will have more than legislation on its hands in the new year.
It has the task of debating and voting on the appointees Trump has announced to head his Cabinet departments and for other top jobs in the new administration.
Prominent Republican Senator John McCain has warned that Rex Tillerson, Trump's choice for secretary of state, will have to explain his relations with Russian President Vladimir Putin, whom McCain has called a "thug and a murderer."
Democrats are also poised to attack the nomination of successful private equity investor and hedge fund manager Steven Mnuchin, who spent 17 years at Goldman Sachs and whose nomination came after Trump's campaign promised to tackle Wall Street influence in Washington.
Nevertheless, Trump is expected to win approval of most, if not all, of his cabinet nominees.
The Senate also is expected to receive a Supreme Court nomination early on from Trump, triggering a likely confirmation war.
Republicans refused to consider Obama's nomination of Merrick Garland last year.