President Barack Obama signed into law on March 23 his landmark health care reform bill that will extend health coverage to 32 million uninsured Americans, The New York Times reports.

“The bill I’m signing will set in motion reforms that generations of Americans have fought for and marched for and hungered to see,” Obama said during the signing ceremony in the East Room of the White House. “Today we are affirming that essential truth, a truth that every generation is called to rediscover for itself, that we are not a nation that scales back its aspirations.”

On the same day the president signed the landmark legislation, Republican opponents to the bill rallied behind a new slogan, “repeal and replace.” Republicans in the Senate have vowed to block—or at least gut—a 150-page “fixes” package to the health care law, which was written under special reconciliation rules. Meanwhile, attorneys general in 13 states, most of whom are Republican, filed lawsuits against the health care bill, labeling it unconstitutional for forcing Americans to buy insurance or face a penalty.

Democrats, however, are urging Republican critics to stand down.

“Now it is a fact,” said Senator Max Baucus (D–Mont.). “Now it is law. Now it is history. Indeed, it’s historic.”