WASHINGTON — The children of lower-income families would continue getting health care under Medicaid, under legislation Sen. Olympia Snowe introduced Thursday.

The program, called State Children’s Health Insurance Program, serves children in families earning up to twice the federal poverty level, or about $33,200 for a family of three. About 14,800 Maine children participate.

But a shortfall in federal funding threatens to cut off coverage for 3,200 children this summer. The entire program begun in 1997 is set to expire Sept. 30.

Democratic congressional leaders are eager to expand and extend the program. But Republican critics are upset that some states expanded it to cover children in families that earn more or to cover adults without children.

Snowe, R-Maine, and Sens. Jay Rockefeller, D-W.Va., and Edward Kennedy, D-Mass., proposed to double funding over the next five years rather than cut it from $15 billion to $5 million as the Bush administration budgeted.

The lawmakers proposed to increase the number of children covered nationwide from 6 million to 9 million over the next five years. The program would also expand to provide mental and dental health care.

“It’s the least we can do as a nation,” Snowe said.