WASHINGTON — Montana Sen. Jon Tester and his fellow freshman Democratic senators joined Thursday to introduce an $80 billion package of middle-class tax cuts, saying they won election in November by vowing to help working families.

“Many of us got elected, if not all of us got elected on the fact that the middle class has been ignored over the last 10 years,” Tester said at a press conference. “We need legislation that will pay some attention to the middle class, will make the middle class vibrant again. This legislation does the kind of stuff for middle class families that Montana sent me here to do.”

Sen. Charles Schumer, D-N.Y., who helped Tester win election through his role as head of the Senate campaign committee, outlined the details of the legislation. He said 2008 will be a referendum on how well the new Democratic congressional majority addresses middle-class issues.

The Middle Class Opportunity Act of 2007 would provide $80 billion in relief from this year through 2010.

The legislation would double the child tax credit to $2,000 in the first year after a child is born or adopted. It would also extend the dependent care tax credit to cover 35 percent of qualified childcare expenses for families earning up to $75,000.

The bill would also provide two years of relief from the alternative minimum tax, or AMT. That is double the one year that President Bush has proposed, Schumer said. Under current law, many more families with incomes between $75,000 and $100,000 may fall under the AMT in 2008, meaning they would end up paying more taxes.

The measure would also consolidate three major college tax deductions into one tax credit that would be more easily understood and applied, they said. It would cover tuition, fees and textbooks and could be used for undergraduate or graduate education.

The bill would also expand the dependent care tax credit for people who take care of their aging parents. Unlike current law, it would allow people to take a credit for qualified expenses paid on behalf of an elderly parent even if the parent doesn’t live with them.

Schumer and the freshmen sponsors propose to pay for the tax breaks through several different measures. They include raising the income tax on people earning more than $400,000; repealing some tax breaks for the oil and gas industry; and by closing the tax gap, or collecting taxes from those who have avoided paying.

The other freshmen Democratic senators at the press conference included Sherrod Brown of Ohio, Robert Casey of Pennsylvania, Amy Klobuchar of Minnesota, Claire McCaskill of Missouri and Sheldon Whitehouse of Rhode Island.

Tax legislation falls under the jurisdiction of the Finance Committee, which Sen. Max Baucus, D-Mont., chairs.

“(Baucus) supports these common-sense provisions and commends Senator Tester for showing early leadership on such an important issue to Montana,” said Baucus spokesman Barrett Kaiser. “As chairman, Max is committed to working together to provide tax relief to people who need it the most.”