WASHINGTON — The U.S. Senate, in a resounding bipartisan vote, approved the outlines of a watershed budget-balancing agreement between President Clinton and GOP leaders on Friday.

The vote on the budget was 78-22, with 34 Democrats joining 44 Republicans to support the plan. Eight Democrats and 14 Republicans voted against it.

Maine’s two Republican senators, Susan Collins and Olympia Snowe, voted for the measure.

“It was truly a bipartisan effort,” said Senate Majority Leader Trent Lott, R-Miss. “We should be proud of it, and it’s an example of what we should do more of in the future.”

The budget resolution sets spending and revenue targets aimed at eliminating the deficit by 2002, which would be the first time since 1969 the budget was balanced. It calls for a tax cut of $85 billion and $115 billion in Medicare savings over five years.

The House passed a nearly identical measure Wednesday. Minor differences between the two versions will not be resolved until after Congress returns from a 10-day recess that began Friday, but the basics of the fiscal blueprint are set in concrete.

However, the budget’s rocky road to House and Senate approval suggests that the next stage — actually enacting the tax and spending bills needed to turn the plan into law — will be extremely difficult.

Republican committee chairmen are bridling at their leaders’ efforts to dictate the terms of legislation to them. Democrats, most of whom were lukewarm or downright hostile to the deal, may be less willing to support the particulars than the broad agreement. And outside interest groups are mobilizing to block deficit reduction measures that come out of their hides.