Obamacare repeal
Trump Administration wants to completely overturn Obamacare. Protesters join together in front of the office of Rep. Carlos Curbelo (R-FL) on August 3, 2017 in Miami, Florida. Joe Raedle/Getty Images

Health care has arguably been the most heated policy topic on Capitol Hill over the decade. After the Obama administration earned a monumental victory in 2010 with the passage of the Affordable Care Act, there have been efforts by Republicans to strike it down with "repeal and replace."

The debate resurfaced Monday after the Trump administration sought to strike down the ACA. The position shift was revealed through a letter sent from the Department of Justice to the Fifth Circuit Court of Appeals, which said the court should affirm the ruling in December by Texas Judge Reed C. O’Connor.

O'Connor ruled that a 2017 tax measure that eliminated the penalty for the uninsured rendered the ACA unconstitutional.

The ruling had faced almost immediate criticism, one of the most notable being California Attorney General Xavier Becerra.

"Today’s ruling is an assault on 133 million Americans with preexisting conditions, on the 20 million Americans who rely on the ACA’s consumer protections for health care, and on America’s faithful progress toward affordable health care for all Americans," Becerra said in December.

Democrats were quick to respond to the Justice Department's decision.

"Last night, the Department of Justice declared the entire law and all of its vital health care protections must go," Senate Minority Leader Charles Schumer said Tuesday on the Senate Floor.

"Make no mistake about it, this is an escalation of the Trump administration and Republicans' attacks on protections for people with pre-existing conditions."

The Supreme Court upheld the ACA in a 2012 decision and rejected a 2015 challenge to the law.

Roughly 21 million could lose health insurance if the ACA is struck down.

In a Wall Street Journal opinion piece in September, Republican strategist Karl Rove urged parties candidates to reach "a draw" with Democrats on health care by discussing "ways to help a broader swath of Americans by making insurance more affordable and accessible overall."

A YouGov poll in December 2017 showed that 31 percent of Americans believed Republicans had repealed the ACA.