Shortly after the election results showed that the House would return to substantive, not just nominal, Democratic control, Rep. Robert H. Michel (R-Ill.), the GOP minority leader, complained: "We are going to be at the mercy of Tip."

The shift of 26 seats from the GOP to the Democrats will strengthen the hand of House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass), but the situation will be far more complex than the return to old-guard Democratic economic policies that Michel's comment suggests.

Instead, the restoration of a working, if tenuous, Democratic majority in the House means that there will be a revival of the party's unresolved internal conflicts.

When President Reagan and a Republican-conservative Democrat majority dominated the agenda, the Democratic opposition could maintain a semblence of unity in shared criticism of governmental policies.

Now, however, the Democrats face the responsibility of developing their economic policy alternatives -- a budget that deals with huge deficits; a jobs program to respond to the highest unemployment in 40 years; productivity incentives, and tax legislation.

All of these challenges will revive the internal conflicts that plagued the Democrats before the election of Ronald Reagan, threatening to redivide the party into conflicting factions:

* Urban liberals, many representing districts with declining industries seeking both direct government support and protection from imports;

* Suburban representatives determined to avoid the "tax and spend" label;

And "Atari Democrats" who advocate a shift in resources away from declining industries into growth sectors of high technology and service industries, along with educational, research and development programs designed to train workers and provide seed money for innovation.

The emergence of the younger "Atari Democrats" -- a teasing name their critics have coined -- signals a basic struggle within the party over how and where federal funds should be spent to revitalize the economy.

While they share with other Democrats the intention to spend more to shore up a crumbling federal highway system, and other traditional public works activities, they are even more determined to use the government's power to speed the development of new technologies in fields like genetic engineering, robotics and automation, and electronics.

According to Rep. Timothy E. Wirth (D-Colo.), the goal of these "Atari Democrats," many of whom represent affluent districts, involves a shift from a concentration on the redistribution of wealth to "the politics of growth."

But there is no consensus on this approach. "You don't have a clear line (for policy initiatives) coming out of the election. You have enough votes to make things happen, but the Democratic Party has a continuing struggle," said Rep. Leon E. Panetta (D-Calif.), a Budget Committee strategist.

Despite these internal conflicts, the saving grace of House Democrats as they seek their economic solutions may well prove to be key Republican Senate leaders.

There is strong pressure within the Republican Party to come up with their own program for two main reasons--many of the Republican House losses were in districts suffering the worst effects of the recession, and most of the Senate races where GOP incumbents barely survived were in states with high unemployment. A move by Republicans to pump more federal money into jobs programs would ease Democratic fears of being tagged once more as big spenders as they move in the same direction.

Sen. Pete V. Domenici, the conservative chairman of the Budget Committee who saw his New Mexico constituents oust their junior senator, Harrison H. Schmitt (R-N.M.), declared after the election that Congress should move forward with a public works program. "Unemployment levels cannot stay at their current levels."

Similarly, Sen. Howard H. Baker (R-Tenn.), who is up for re-election in 1984 and whose daughter was defeated in a bid for a House seat on Tuesday, said, "I think it's almost certain there will be a jobs program of some sort, and there should be."

This kind of drive is likely to get support from such senators as John H. Chafee (R-R.I), John C. Danforth (R-Mo.) and David F. Durenberger (R-Minn.), for whom Reaganomics was a liability pushing each of them within a few percentage points of elective oblivion on Nov. 2.

At the same time, many of the Republican senators up for reelection in 1984 see in the election results strong reason to shift away from the Reagan administration's essentially anti-government stance towards essentially Democratic proposals for government intervention to ameliorate the effects of the recession and to provide farmers with some economic stablity.

Among the GOP senators up in 1984 are Rudy Boschwitz (Minn.), William S. Cohen (Me.), Mark O. Hatfield (Ore.), Nancy L. Kassebaum (Kan.), Charles H. Percy (Ill.) and Larry Pressler (S.D.), all of whom represent states where the recession is severe and showed its effects in the election results.

The first real test of the assertiveness of House Democrats will come not on an economic issue, but on a series of party discipline questions that will be raised when the party organizes in caucus before the start of the 98th Congress next year.

While seemingly unrelated to economic policy, these discipline issues will be, in part, a test of the strength of the Democrats' liberal wing, and of the willingness of the Democratic caucus to punish members who this year and last abandoned the leadership to support President Reagan.

The key Reagan-Democrat in the House, Rep. Phil Gramm (D-Tex.), is just about guaranteed to be removed from the Budget Committee. The more significant test will come on anticipated proposals to take away his assignment to the Energy and Commerce Committee, and perhaps to eject him from the Democratic caucus altogether.

In addition, there are some liberals talking about applying severe penalties on two other Democrats whose loyalty to the party has been questioned: Reps. G. V. (Sonny) Montgomery (D-Miss.) and Lawrence P. McDonald (D-Ga.).

In terms of economic policy, a willingness to take such steps by a majority of the Democratic caucus would suggest a willingness for direct confrontation with Reagan. It would also be a signal of declining strength within the Democratic Party of the Conservative Democratic Forum -- the Boll Weevil Democrats -- many of whom were key Reagan supporters in the 97th Congress.

Along similar lines, there is some speculation among House members that an O'Neill ally, Rep. Edward P. Bolland (D-Mass.), will challenge Jamie L. Whitten (D-Miss.) for the chairmanship of the Appropriations Committee, a step that would shift significant power over the allocation of money into more liberal hands. But most people do not expect the challenge to materialize.

However, the addition of 26 new Democrats (and the elimination of 26 Reublican votes) will not push the House as far to the left as the numbers might suggest. While Democrats will outnumber Republicans 269 to 166, most of the incumbent Southern conservative Democrats won reelection and many of the newly elected Democrats won on tickets calling for restrictions on government spending.

"I was running against the leadership of both parties," said Robert Torricelli, a Democratic winner in New Jersey. "We have to show we can be as tough as any hard-nosed Republican," he said, noting that some liberal Democrats persisted in supporting "programs that were decent even though they were failing."

Moreover, the death and retirement of a number of House members will have significant, if subtle, consequences for economic policy.

Over the past two years, three Republicans who acted as floor watchdogs, restricting the maneuvers of the Democratic leadership and forcing embarrassing votes -- Reps. Robert E. Bauman (Md.), John Ashbrook (Ohio) and John H. Rousselot (Calif.) -- have gone. Ashbrook died and the other two were defeated.

While these three may be replaced, it will be difficult to match their knowledge of parliamentary procedure, and the effect will likely be to give the Democratic leadership more leeway in controlling floor action.

At the same time, however, the Democrat who had assumed a role of trying to mediate party disputes over economic questions and to formulate policy -- Rep. Richard Bolling (Kan.) -- has retired, leaving a significant vacuum.

The defeat and retirement of numerous Democrats on key committees has created a situation where the Democratic leadership in the House has the possibility of strengthening its control.

There are three Democratic vacancies on Appropriations and two on Ways and Means, both of which may get another Democratic seat because of the overall shift to the Democrats in the House. While it is difficult for the House leadership to control the selection of members for these choice assignments, the addition of O'Neill allies to these panels would give him far more control over fiscal policy than he now has.

Conversely, many expect the 98th Congress to be O'Neill's last as speaker. As the dueling for the leadership openings that will develop with his departure intensifies, it will be increasingly difficult to develop unified positions on issues.