By electing near-record numbers of newcomers to Congress and the governorships, voters in Tuesday midterm election have expanded the area of two-party competition and evened the balance between liberals and conservatives in both parties.

The new Congress - with three more Republican senators and a dozen more GOP House members - is expected to be more amenable to the efforts President Carter has promised to reduce federal deficits, but probably more resistant to such foreign policy initiatives as a strategic arms limitation treaty with the Soviet Union.

In 1980 reelection terms, Carter now faces a Republican Party with a significantly stronger grass-roots base and a set of presidential hopefuls with burnished political credentials.

While no official compilations were available, there were indications of wide variations in the voting turnout. About half the states reported larger votes than in 1974, the previous off-year election, while the other half noted declines of various sizes. Close contests and the presence of ballot initiatives on spending policy were the main lures to the voters.

In an election which saw relatively modest overall shifts in the heavily Democratic Party ratios in Congress and the state capitols, the standout features were the defeat of five prominent Senate Democratic liberals, the rout of the Democrats in Minnesota, the expansion of GOP strength in the Midwest and South and the capture by Republicans of key governorships in Pennsylvania and Texas.

The victory of Republican William P. Clements Jr. (R) in the Texas gubernatorial battle broke a historic Democratic monopoly on that office, as did the election of Rep. Thad Cochran as the first popularly chosen Republican senator from Mississippi.

But Democrats noted that there was no massive repudiation of Carter or his party visible in the returns, and there were signs in referendum voting that the anti-tax fever may be a little less intense now than it was last summer.

The new lineup of party strength is:

Senate - 59 Democrats and 41 Republicans, a net gain of three for the GOP. Republicans took two seats from the Democrats in Minnesota and single seats in Colorado, Iowa, maine, Mississippi, New Hamphshire and South Dakota Democrats captured GOP seats in Massachusetts, Michigan, Nebraska, New Jersey and Oklahoma.

House - 276 Democrats and 159 Republicans, a net gain of 12 for the GOP. This calculation could change slightly if the outcome of two very close races - now split between the parties - should change.

Governorships - 32 Democrats and 18 Republicans, a net gain of six for the Repulicans. Democrats lost only five state capitols, however, because they took over from an independent in Maine. The GOP pickups came in Minnesota, Nebraska, Nevada, Oregon, Pennsylvania, South Dakota, Tennessee, Texas and Wisconsin. Democrats took over governorships from the GOP in Kansas, New Hampshire and South Carolina.

Legislatures - The Republicans made a net gain of about 250 legislative seats, gaining control of about 13 additional legislative houses and increasing from six to 13 the number of states in which they control both houses.

All of the GOP gains were modest by historical standrards, but, except for the House, they exceeded the pre-election predictions of Republican leaders.

Republican National Chairman Bill Brock called it "a banner day" for his party and said that after the setbacks of 1974 and 1976, "we have established our momentum."

Brock said the legislative victories were particulary important in giving the GOP leverage for the reapportionment battles that will follow the 1980 census and in providing a new pool of younger candidates on which to draw in future years.

Democratic Naional Chairman John C. White drew satisfaction from the fact that "for the first time in the postwar era, Democrats have retained more than 60 percent of the House senates in three successive elections."

And he noted that at least 48 of the 52 House Democrats with the highest consistency of support for Carter programs had been reelected.

Although 16 of the 28 senatorial and gubernatorial candidates for whom he campaigned since Labor Day were defeated, Carter told reporters, "I thought they did very well." Many of Carter's appearances were deliberately targeted in difficult races for the Democrats.

White House press secretary Jody Powell called it "one of the best off-year elections any president has had," but other White House officials expressed concern about the chances of a SALT agreement with the Soviet Union in a more conservative Senate.

Putting aside the predictable partisan reactions, what was striking about the results of Tuesday's voting was the eagerness the voters showed to entrust the government to new hands.

New faces were chosen in 20 of the 35 Senate races and 20 of the 36 governorships decided this year, exceeding the turnover in any previous election in this decade. The 77 new House members comprise the largest entering class this decade except for the Watergate election of 1974.

In casting about for officials who might have more luck coping with the economic problems that dominated the campaign, voters once again ignored party labels and split their tickets with impunity.

One of the most dramatic examples of that independence came in New Hampshire, where Democrat High Gallen upset three term Gov. Meldrim Thompson, Jr. (R), a nationally known conservative spokesman, while the conservative Senate candidate Thomson had recruited, airline pilot Gordon Humphrey (R), surprised Sen. Thomas J. McIntyre (D-N.H.).

There were similar, if less dramatic, ticket-splitting demonstations in Colorado, Kansas, Maine, Michigan, Nebraska and South Carolina, among other states.

The result was a resumption of the historic trend toward the spread of two-party competition into all the states, a trend which had been interrupted by the GOP reverses following Watergate.

In addition to their Texas and Mississippi Breakthroughs, Republicans grabbed off additional House seats in Arkansas, Georgia, Kentucky and South Carolina - states where they had been stymied since the 1960s.

As both Brock and Democratic pollster Peter D. Hart noted, Republicans restored their traditional Midwest base by capturing governorships in Minnesota, Nebraska, South Dakota and Wisconsin, while retaining control in Ohio, Michigan and Illinois.

But Democrats showed their vitality by strengthening their position in the band of northeastern states from New York to Maine, where they now control all but one governorship, and by maintaining their edge in the western states, where the reported unpopularity of Carter's water and farm policies was expected to have damaged Democratic candidates. As it turned out, Democrats lost only one governor, one senator and a net of three House seats in the West.

The GOP gubernatorial victories - particularly in what is now a solid band of Republican-controlled states from Pennsylvania west to Iowa and Minnesota - were viewed by politicians as particularly important for 1980 presidential politics.

Carter and Vice President Mondale had campaigned hard for the Democratic gubernatorial candidates in all those states, only to see them lose.

The defeats of Pete Flaherty (D) by Richard L. Thornburgh (R) in Pennsylvania and Lt. Gov. Richard Celeste (D) by Gov. James A. Rhodes (R) in Ohio were particularly vexing to the White House.

Both Flaherty and Celeste had been early Carter allies in 1976, and their help was important in carrying their states for critical Carter victories in both the presidential primaries and the general election.

Had Thornburgh and Celeste been elected governors, Carter would have had a clear advantage in 1980. As it is, national chairman White said, "we'll have to go in and set up our own organizations" in those states and others, including White's native Texas, where Democrats lost the governorships on Tuesday.

To the extent that there was an ideological trend in Tuesday's voting, it seemed most clear in the Senate. The five liberal Democrats who went down to defeat - McIntyre and Sens. William D. Hathaway (Maine), Floyd K. Haskell (Colo.), Dick Clark (Iowa) and Wendell R. Anderson (Minn.) - had comprised the core of liberal strength on both foreign policy and domestic welfare issues.

Their defeat increased the ideological isolation of Sen. Edward M. Kennedy (D-Mass.), who had campaigned for all of them.

But Kennedy's own state of Massachusetts, as well as Michigan, Nebraska, New Jersey and Oklahoma, elected new Democratic senators at least marginally less conservative than their Republican predecessors.

And in such southern states as Alabama and Arkansas, the new Democratic senators will probably be more progressive than their Democratic predecessors.

Dr. Jack Carlson, chief economist for the U.S. Chamber of Commerce, expressed the general view when he said the new Congress "will be more moderate in some of its growth and federal spending programs."

He said there was a net gain in the Senate of four votes for people "more oriented to market solutions, as opposed to governmental solutions," and an increase of 15 votes in the House for "market-oriented" members.

Russell Hemenway, an official of the liberal-oriented National Committee for an Effective Congress, called the Senate "the disaster area" in the election, but said 31 of the 40 House endangered incumbents it supported had won. Paul Weyrich, director of the conservative-oriented Committee for the Survival of a Free Congress, said he was "favorably surprised" by the congressional outcome.