With White House staff members in control of the floor, the Democratic midterm conference today rejected a move to tell President Carter to spare domestic welfare programs from the budget cuts he is planning for next year.

The 3-to-2 vote against the liberal-backed measure to keep all domestic programs funded at least at current levels ended the one major debate at the mini-convention.

The vote pleased Carter aides, who had lobbied hard to kill the resolution, and led Democratic National Chairman John C. White to claim Carter was "in tune with his party" in his anti-inflation budget-cutting plans.

With White House backing, the delegates also called on Congress to approve a new strategic arms limitation treaty with the Soviet Union, when it is negotiated, and to pass a national health insurance program within the next two years.

In their final four-hour session, the grass-roots party representatives gave their blesing to the current Carter policies on everything from energy to inflation ot urban issues.

On several of the domestic issues, convention officials and White House aides had rewritten the draft resolution to embrace some of the liberal objectives.

But they drew the line on a budget resolution, sponsored by United Auto Workers President Douglas Fraser, which said domestic welfare progams should "in no case" be funded at less than the current services budget.

The current services budget is the level of money nedded to provide all existing services to all eligible recipients at rising price levels.

Fraser argued that unless the party conference objected, there would be "drastic cuts in vital social service programs" in Carter's January budget for fiscal 1980, which begins next Oct. 1.

But as White House aides, led by senior presidential assistants Hamilton Jordan, Tim Kraft and Frank Moore, moved out on the floor, Party Chairman White and Gov. James B. Hunt Jr. of North Carolina urged the delegates not to "tie the president's hands."

The Fraser resolution was defeated on an 822-to-521 roll-call vote. The convention then endorsed a White House-backed substitute saying "it the budget -- domestic as well as defense -- be fully scrutinized and that a special effort be made to avoid unnecessary reductions in programs which aid the poor and the disadvanteged and... our urban areas."

Before the vote, the mini-convention heard Vice President Mondale warn that if Democrats "don't end the everrising cost of living, we will be driven out of office as we were by the Vietnam war."

Mondale's comment was the administration's reply to yesterday's assertion by Sen. Edward M. Kennedy (D. Mass.) that retrenchment on domestic programs would divide the Democratic Party as badly as the Vietnam war did in the 1960s.

"If we don't end inflation," the vice president said, "it will stop all our efforts for social progress.... Inflation well make a progressive nation a nasty, uncaring, illiberal society.... It has happened to other societies and it can happen to us."

Mondale set the stage for the budget resolution debate when he told the delegates, "Don't worry about the compassion of this president" when it comes to budget cutting.

"It will not be just the domestic programs that will be analyzed," Mondale promised. "So will the defense budget."

But Fraser, who sat with Kennedy at a panel session Saturday when the Massachusetts senator reeled off a long list of health programs he said the Office of Management and Budget is proposing to cut off witout a nickel, told the delegates the issue was not one of "trusing" Carter.

The White House-backed resolution, he said, "sanctions cuts in vital social service programs.... We are told that times are changing and we must change with the times, but I hope the Democratic Party never changes in its commitment to those who are most in need of a helping hand from their government."

But White, rebutting Fraser, said the union leader's resolution would "deny the president the right to reorganize programs, to investigate them for fraud, or to see if they're out of date."

The roll call of states showed support for the defeated liberal resolution coming from expected quarters like Massachusetts, Wisconsin and California. But White House officials used their influence on leaders of several large state delegatons, and grinned when Illinois cast a unanimous vote against Fraser's resolution.

Afterward, no one seemed certain how much influence it would have on the spending decisions Carter and Congress will make next year. Fraser said he thought the president "will have to listen" when 40 percent of the midterm delegates dissent from his reported budget priorities.

But White said he thought the vote showed "the president and his party are in tune with each other," and said grass-roots support for domestic economies was probably greater than that registered among what he called "the activist, issue-oriented people here."

White House press secretary Jody Powell said, "If we had lost it 2 to 1, the president still would have had to go ahead and do what has to be done." But he noted, "We will be dealing with this budget question in Congress for months, and it's nice to have this kind of backing from this kind of party gathering."

White House control of the midterm conference had never been in serious doubt. And White, who handled the negotiations that ultimately checked the liberal dissent with a few minorverbal concessions,m declared the meeting "unusually successful."

"This is the first time in history," he said, "a president and his administration have gone before his party and responded directly to its questions and concerns."

But White said that despite that outcome, he was not prepared to say that such conventions should be mandated for future years.

The conclave cost the party about $650,000 and the expenses incurred by individual delegates added substantially to the total. The only previous conference was held four years ago, to adopt a party charter.

After the budget resolution was passed, delegates began an exodus for the airport, leading to passage of many final resolutions en bloc. But before they left, the delegates reaffirmed a number of planks of the 1976 platiform, urged the Senate to support a SALT II agreement once it determines "it to be well conceived, effective and verifiable," and called for passage of national health insurance by the 96th Congress.