THE NATION - 1st veto override may come on healthcare - A plan to expand the program insuring low-income children has wide support.

Now, almost 10 years later, President Bush is threatening to veto federal legislation that would renew the same partnership -- the State Children's Health Insurance Program -- and expand it to cover more of the nation's nearly 9 million uninsured children.

If he follows through on that threat, Bush could face a first in his presidency: a veto override.

The bill is considered Washington's most important legislation this year on health coverage.

And Bush's fellow Republicans are worried that Democrats may do more than back the president into a corner -- they could use his opposition to tar GOP incumbents in next year's elections.

If the House and Senate approve the bill and Bush vetoes it, some Republicans say, there is a good chance that many in his own party would join with Democrats in overriding him.

Many Republicans are "very nervous," said Sen. Gordon H. Smith (R-Ore.), a supporter of a compromise formula that Bush opposes. "On the one hand, you've got the veto threat. On the other hand is the political importance of expanding healthcare for children. This is public policy broadly supported by the American people."

"I personally believe there is a reasonable chance he'll be overridden, but I don't want to make any predictions," said Sen. Orrin G. Hatch (R-Utah), one of the authors of the original program.

On Thursday, a 17-4 vote in the Senate Finance Committee to approve the compromise approach showed how unpopular Bush's position is in his own party. A majority of the panel's Republicans joined Democrats in voting to expand the program by $35 billion over five years, far more than the $5 billion in additional spending Bush has proposed.

"The president might be better off if Congress does deadlock over this," said G. William Hoagland, a former senior GOP budget aide in the Senate. "If they hand the president a bill, the risk of an override of his veto would be very high."

"A lot of states and a lot of Republicans are invested in this," said Hoagland, now a policy advisor to health insurer Cigna Corp. "I think this is a dangerous one for him."