When President Reagan telephoned his congratulations last Wednesday, Sen. Richard G. Lugar was ready with a message of his own.

"Now is the time to put our heads together," the Indiana Republican told him. "We have to come up with some solutions to our problems out here. It's not only important to the nation, but it's vital to the Republican Party."

Lugar was speaking with some authority. On a day when Republican candidates were demolished across the Midwest, Lugar was the party's biggest winner in the region.

GOP defeats were as deep as they were wide. Republicans lost 12 midwestern House seats -- including the one once occupied by Abraham Lincoln -- and five governorships. They came within a whisker of letting a fifth governorship and two Senate seats slip away.

Democrats captured both houses of the state legislature in Minnesota, Illinois, Iowa, Michigan, Missouri, Ohio and Wisconsin. Voters in Ohio, a state which has produced five Republican presidents, elected Democrats to every state office for the first time since 1936.

The election carried a powerful symbolic message for the GOP: the politics of turmoil has overtaken the nation's most economically troubled region, devastating the party's traditional base.

Republicans have held the governorships of Ohio, Michigan, Iowa and Nebraska through good times and bad -- including the Watergate years. Governors in these states, master politicians on their home turfs, have provided leadership for the party's moderate center.

In 1983, they'll all be gone: William G. Milliken after 13 years in Michigan, James A. Rhodes after 16 years in Ohio, Robert D. Ray after 14 years in Iowa. Gone also will be Minnesota's Albert Quie, Wisconsin's Lee Sherman Dreyfus and Nebraska's Charles Thone. All but Thone had decided not to run again.

Each, except Ray, is being replaced by a rambunctious Democrat. This may have a powerful impact on the nation's political equation in 1983 and 1984.

The newly elected Democrats -- particularly Ohio's Richard Celeste, Wisconsin's Anthony Earl and Michigan's James P. Blanchard -- intend to stake a claim on the direction of the Democratic Party and on national policy toward the region.

"People are unhappy with the fact that our midwestern governors have not only acquiesced in everything that has happened in Washington during the last two years, but they have been among the most prominent proponents of it," said Earl. "These policies have been very unfavorable to the Midwest whether they've been in agriculture, New Federalism or education."

Each of the new midwestern governors will face huge deficits, caused in part by the recession and in part by GOP-initiated tax policies in their states.

"Celeste is going to be focused on Ohio, but he'd like to be a regional spokesman and build an effective coalition of the new governors," said Paul Costello, press secretary to the Ohio governor-elect. "He plans to make sure the Great Lakes states use their muscle to say, 'We need a fair share of the national pie.' "

The midwestern gubernatorial campaigns centered to an unusually large extent on national economic issues.

National agricultural policy, for example, was a major issue in the election of Vietnam war hero Robert Kerrey in Nebraska.

Economic policy dominated the political dialogue in Ohio where Celeste called Republican Rep. Clarence J. Brown "Ronald Reagan's Ohio cheerleader" and said the president's New Federalism proposals were an attempt "to pass the buck without the bucks."

The newly elected governors in Ohio, Michigan, Wisconsin and Minnesota each have long and close ties to the Democratic Party. "The election may signal a rebirth of the Democratic Party starting in the heartland," said Blanchard, who wrote the Chrysler bailout bill as a congressman. "It should send a message to Ronald Reagan to moderate his tone."

The new governors also have close ties to organized labor. Labor has a bigger claim on Blanchard, who won the primary and the general election with help from the United Auto Workers, the AFL-CIO and the Michigan Education Association, than on any other governor.

"The key question is what will we do with our gains," Blanchard added. "Will we come in with more warmed-over New Deal or something new? People see Reagan looking backward, but they haven't seen an alternative yet from the Democrats."

The impact of the election on 1984 Democratic presidential politics is less clear. The intellectual soul of the liberal wing of the Democratic Party has largely rested in the region in recent years. With the exception of 1960, the party has picked a presidential or vice presidential nominee from the Upper Midwest every four years since 1952.

The new governors give Democrats a power base they lacked in 1980. Two midwesterners are expected to be 1984 presidential candidates: former vice president Walter F. Mondale of Minnesota and Sen. John Glenn of Ohio.

Glenn forces view Celeste's nomination as a big plus. "Celeste and Glenn pulled the political plug for one another. They're very close political allies," said Ohio Democratic chairman Paul Tipps. "Dick Celeste has the capacity to help Glenn around the country."

Mondale received no such boost in Minnesota. He has never been close to Gov.-elect Rudy Perpich, who defeated Warren Spannaus, one of Mondale's closest friends, in the Democrat-Farmer-Labor primary. And Perpich aides delight in telling reporters that one of the first telephone calls Perpich received after the primary win was from Sen. Edward M. Kennedy (D-Mass.).

For Republicans and Reagan, the Midwest is full of danger signs. Midwesterners who voted last Tuesday supported Reagan over Jimmy Carter by 47 percent to 39 percent two years earlier, according to ABC exit polls. Reagan, drawing on a coalition of ethnics and blue-collar workers, carried every state in the region, except Minnesota.

Yet 58 percent of them don't think Reagan should seek reelection, and 80 percent disapprove of the way he is handling his job as president. According to the poll, 71 percent of midwesterners disapprove of Reagan's handling of unemployment, and 82 percent don't like the way he is handling the problems of the Social Security system.

Republican hopes of a permanent party realignment went out the window. Sixty-nine percent of midwestern union members voted against Republican congressional candidates, the ABC poll found. "If Republicans don't rethink their philosophy, they're going to become the unicorn of American politics," said Tipps.

Amid the disaster, the poll held out two encouraging signs for Reagan. In matchups with the two top Democratic challengers, the president led Kennedy by 52 to 48 percent, and Mondale by 51 to 49 percent. Voters also haven't given up on the GOP; 45 percent said Republicans can deal with the nation's worst problems better than Democrats.

This is why Lugar's message to Reagan was especially important. In a state with an 11.4 percent unemployment rate, he won not by disavowing the president, but by building an effective political organization and advocating programs to put people back to work by shoring up basic industries, such as housing, steel, agriculture and auto manufacturing.

He called it "Reaganomics plus." To date, he hasn't sold Reagan on the idea. When Congress passed a housing bill last summer that Lugar claimed would create 500,000 jobs, Reagan vetoed it.

"If the president had signed it, I think more Republicans would have been elected," Lugar said.