WASHINGTON – Legislation to give additional months of unemployment benefits to people who have been out of a job for more than half a year cleared a key hurdle Tuesday that guarantees it will soon pass the Senate.

The bill also would keep doctors from absorbing a crippling cut in Medicare payments and extends insurance subsidies for the jobless through December. It would add $132 billion to the budget deficit over the next year and a half.

Eight Republicans, including Maine Sens. Olympia Snowe and Susan Collins, voted with Democrats to defeat a GOP filibuster of the measure, setting up a final vote today.

The measure illustrates the great extent to which direct help for the jobless and the poor makes up a large portion of Democrats’ election-year agenda on jobs — and that it threatens to squeeze out other items on that agenda amid concerns about a budget deficit projected at a record $1.6 trillion this year.

Democrats also hope this week to separately finish work on a far smaller job-creation measure blending additional highway spending with new tax breaks for firms that hire the unemployed. The Senate could clear the measure for President Obama’s signature by Friday.

Tuesday’s larger bill also provides the annual extension of $26 billion worth of tax breaks for businesses and individuals that are popular with senators in both parties.

The $66 billion cost of providing the extended unemployment checks is added directly to a budget deficit expected to hit $1.6 trillion this year. In states with the highest jobless rates people are eligible to receive benefits for up to 99 weeks. A 65 percent health insurance subsidy for the unemployed under the COBRA program adds about another $10 billion. Federal cash to help states with Medicaid adds about $25 billion more.

“Even though these programs may be good for your state, a senator has an obligation to stand up and say ‘no more,’ ” said Sen. George Lemieux, R-Fla. “No more spending our kids’ future. No more bankrupting the promise of this country.”

But Democrats said it would be heartless to cut off unemployment benefits for people mired in joblessness after the worst recession in decades. They also say that the unemployment benefits inject demand into the economy, helping to lift it.

“This is not just some technical bill,” said Sen. Max Baucus, D-Mont. “This bill helps real people. Failure to enact this bill would cause real hardship. Failure to enact this bill would cost jobs.”