U.S. President Barack Obama on Tuesday defended his signature healthcare overhaul ahead of a vote to repeal it in the House of Representatives.

In a White House statement, Obama said because of the Affordable Care Act passed last year, Americans now “have greater health security than they did a year ago…Small businesses across the country can take advantage of a new health care tax credit to offer coverage to their employees.”

He said he’s “willing and eager to work with both Democrats and Republicans to improve” the reform, but said it can’t go backwards.

“Americans deserve the freedom and security of knowing that insurance companies can’t deny, cap, or drop their coverage when they need it the most, while taking meaningful steps to curb runaway health care costs,” said Obama.

A landmark legislation rammed through Congress by Obama and Democrats, the Affordable Care Act is facing a public backlash and Republican efforts to repeal it.

Republicans are in control of the House but not the Senate, limiting their power to overturn the healthcare law. House Republicans have scheduled a vote on repealing the law for Wednesday, which is likely to be only symbolic since Democrats still control the Senate. Even if it passes both chambers, Obama can still veto it.

Making the case against Republican push to repeal the reform, a report released by Health and Human Services Department Tuesday said 1 in 2 non-elderly Americans have at least one pre-existing condition that could deny them healthcare coverage without the healthcare reform.

Prior to the healthcare reform, in the vast majority of states, insurance companies in the individual market could deny coverage, charge higher premiums, and/or limit benefits based on pre-existing conditions.