WASHINGTON -- As the battle over health care legislation built Monday toward a weekend crescendo, congressional Democrats considered trying to pass the controversial Senate version without voting for it -- a tactic that Republicans and independent analysts warned could be politically treacherous and perhaps unconstitutional.

Under the plan, the House would approve the Senate bill by "deeming" it to have passed, as part of a separate measure governing the rules of a House debate on a follow-up health care measure. That follow-up legislation will be designed to change certain controversial portions of the Senate-passed version, a path more palatable to House Democrats who fear that voting for the Senate bill could backfire against them in elections this fall.

The maneuver would enable House members to avoid casting a politically risky vote on the Senate package, and to say they voted only for the more popular follow-up measure.

"Many of our members would prefer not to have voted for the Senate bill," said House Democratic Caucus Chairman John Larson of Connecticut. Once the Senate legislation is "deemed" to have passed, as part of the rule governing debate, the House would vote only on the follow-up health care measure, known as a budget "reconciliation" bill.

But using such a dicey procedure to enact President Barack Obama's biggest domestic initiative -- the most far-reaching social policy change in decades -- could inflame a public that is already annoyed at the legislation's tortured path and disgusted with Congress.

"This sort of thing does happen all the time. But in the health care debate, Republicans have been effectively arguing Democrats are using exotic procedures to pass important legislation," said Rutgers University political science professor Ross Baker. "That's a tough argument to refute."

Legal experts also raised concerns.

Stanford University law professor Michael McConnell wrote Monday in The Wall Street Journal that such procedures are unconstitutional. He cited a 1998 Supreme Court ruling that once one house of Congress approves an "exact text," the other house must pass "precisely the same text" before the president can sign it into law. That's been the generally understood principle of how a bill becomes a law for centuries.

But Stanford public interest law professor Pamela Karlan wasn't so sure. "It's kind of complicated," she said, because, as she and others said, it's not entirely clear what "same text" or "exact text" means.

Regardless, the move would be red meat to already-outraged conservatives. "It opens up an entirely new front in the war against what they're doing," said Michael Franc, vice president of government relations at Washington's Heritage Foundation, a conservative research group.

Democratic leaders hope to enact health care legislation by this weekend, after more than a year of debate. One way or another, the House must pass the version that the Senate approved Dec. 24 and send it to Mr. Obama to sign into law.

Republicans quickly fired back about the strategy. "It's very painful and troubling to see the gymnastics by which they're going to avoid accountability," said California Rep. David Dreier, the House Rules Committee's top Republican.

Many House Democrats have problems with the Senate bill, including its excise tax on high-end insurance policies, the lack of a government-run insurance program and a special grant to Nebraska for Medicaid subsidies.

The reconciliation measure is expected to contain several House-inspired "fixes," such as delaying the excise tax's implementation until 2018 and raising the limits on who would be subject to it, providing additional Medicaid aid for all states and increasing government help for lower- and middle-income consumers' premiums. Those changes, on the other hand, would raise the legislation's costs.

Democrats control 253 of the 431 House seats -- four seats are vacant -- so 216 votes are needed for passage. There are blocs of wavering Democrats, including about a dozen who want tougher anti-abortion language, 54 "Blue Dog" moderates to conservatives worried about its cost and a handful of liberals who think the bill is insufficient.

Thirty-nine Democrats opposed the House measure in November, and virtually none of those said they are switching.

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.