WASHINGTON — President Barack Obama sees expansion of government health insurance to millions of lower-income children as a first step of several to come in providing coverage for all Americans.

Ending a two-year effort by Democrats, Obama signed legislation Wednesday that will allow about 7 million children to continue coverage through the State Children’s Health Insurance Program and allow an additional 4 million to sign up.

“The way I see it, providing coverage to 11 million children through CHIP is a down payment on my commitment to cover every single American,” Obama said at a White House bill-signing ceremony.

The measure was similar to two bills vetoed by former President George W. Bush. It was pushed through both the House and Senate by Democrats eager to give Obama an early victory on health care.

Most lawmakers and advocacy groups in the health reform debate acknowledge that the next steps toward reform will be harder than expanding SCHIP, given the increasing federal deficit.

More ambitious changes envisioned by Obama will face entrenched interests in the health care community and Republicans who oppose expanding government-funded insurance.

“Republicans are committed to making health care more affordable, more accessible and offer more options to American families,” said Rep. Roy Blunt, R-Mo. “Unfortunately, the only options we’ve seen so far this Congress would push us to a one-size-fits all government-run system.”

Obama acknowledged the difficulties of reforming health care at Wednesday’s bill-signing ceremony “It won’t be easy; it won’t happen all at once,” the president said. “But this bill that I’m about to sign, that wasn’t easy either.”

Since August 2007, the House has voted seven times to expand the children’s health insurance program. Opposition from Bush helped stiffen Republican resolve and helped block passage of the measures.

During final debate Wednesday before the bill passed the House, 290-135, Republicans criticized the cost of the measure. They also criticized allowing into the program an estimated 2.4 million children who otherwise might have access to private insurance.

“This debate is about, do we want a children’s health insurance program that covers every child in America with state and federal dollars regardless of their ability to pay?” said Rep. Joe Barton, R-Texas. “Do we want to freeze out the private sector for health insurance?”

But supporters said that ensuring children had access to adequate health care was a matter of priorities. Rep. Frank Pallone, D-N.J., said an estimated 4 million people have lost employer-sponsored insurance in the past year.

“Do they keep their families’ health insurance or do they put food on the table at night? During this economic recession, these kinds of decisions are unfortunately becoming more common,” Pallone said.

The bill extends health care benefits to legal immigrant children and pregnant women.

The Immigration Policy Center’s Director, Angela Kelley, issued the following statement.

“It’s a breath of fresh air that the new Congress and President overcame the politically-charged immigration debate that has, for some time, stymied this important legislation. For years, legally-residing children and pregnant women have been denied federal health care benefits during their first five years in the United States. The new law is welcome news as no child should have to wait five years to see a doctor or get a vaccination.