President Reagan departed for Europe last night in search of a remedy for what his senior aides say has been one of the most disastrous political and symbolic episodes of his presidency, his planned visit to the German military cemetery at Bitburg.

Officials in West Germany and the United States say the Bitburg controversy was caused by mistakes in both governments. They said that numerous officials in Bonn and Washington share responsibility for a series of blunders that threaten to overshadow Reagan's original purpose in celebrating the 40th anniversary of the end of World War II in Europe.

The officials said the controversy had its origins in three separate, but parallel, decisions.

The first was Reagan's decision not to visit the Nazi death camp museum at Dachau.

The second was the German-American decision that Reagan and Chancellor Helmut Kohl lay a wreath at the Kolmeshoehe Cemetery, not far from the Bitburg U.S. Air Force Base, on Sunday.

The third decision, made in Washington in response to public outcry over the scheduled Bitburg visit, was to add the Nazi death camp site at Bergen-Belsen to Reagan's itinerary.

These decisions followed a Nov. 30 meeting at the White House when, according to White House officials, Kohl made an emotional plea to Reagan asking that the president join him in a reconciliation ceremony like one Kohl had held with French President Francois Mitterrand the year before at Verdun, site of a major World War I battle.

Kohl asked Reagan to visit a German military cemetery but did not specify which one.

"Reagan, an emotional man, acted very much in character: He immediately consented and ordered aide Michael K. Deaver to accommodate Kohl's wishes," former White House communications director David R. Gergen wrote recently.

In the early planning for Reagan's visit, both governments apparently considered a visit to the Dachau death camp site near Munich. A West German official said his government fully expected that an American president would want to make such an appearance to honor victims of the Holocaust.

On Jan. 20, the West German news magazine Der Spiegel reported that Reagan might visit Dachau; a Bonn government spokesman confirmed that it was under consideration.

This report came at a critical time at the White House. Chief of staff Donald T. Regan was about to take over from James A. Baker III. Deaver had announced his plans to resign in May after the president's European tour.

In a meeting with senior aides, including Deaver, the president expressed the view -- later amplified in a news conference -- that the trip should look forward, not back in time. Reagan said that he didn't want to visit Dachau, and that he had the impression the West Germans didn't want him to either.

Deaver was described by one associate as "surprised" by Reagan's reaction; he went back to draw up a new itinerary. There have been reports that Nancy Reagan also objected to a concentration camp visit.

A West German official said a concentration camp site, where Reagan could pay tribute to victims of the Holocaust, was part of Bonn's original proposed itinerary. It was assumed that this would be the main event of a day that also would include an appearance before German and American military personnel and at a military cemetery.

But the same official said there also were possible domestic political problems connected with the Dachau visit, in part because far-left, anti-American activists belonged to the Dachau Memorial Commission, and the Germans feared anti-American protests at Dachau.

In mid-February, after the White House had revised Reagan's itinerary, spokesman Larry Speakes announced that Reagan would not spend V-E Day, May 8, in West Germany, but rather would deliver a speech that day to the European Parliament in Strasbourg, France. Officials cited Reagan's desire not to "rekindle" past hatreds.

Shortly thereafter, Deaver left for the first advance trip to Germany. At this point, the Dachau trip apparently had been scrubbed for Sunday, but both governments had agreed on a visit to the Bitburg air base, a future site for cruise missile deployment, and the nearby military cemetery. The cemetery was choosen by "technicians," one official said, because of its proximity to a U.S. air base and for security reasons.

For more than two decades, American, French and German military personnel had conducted annual ceremonies there honoring war dead.

Deaver did not take note of any SS graves on the day he visited Bitburg in late February. Some White House and West German officials later blamed this on snow covering the graves.

Deaver has not commented on it publicly, but has told friends that the West Germans assured him that there was nothing embarrassing about the site.

Deaver departed for a second advance trip March 19. Two days later, in a news conference, the president said he did not want to visit Dachau because it would reawaken "the passions of the time." He also contended that today's German population has had a "guilt feeling that's been imposed on them and I just think it's unnecessary." Reagan quoted Kohl as agreeing with this view.

Deaver visited Bitburg again on his second advance trip. But apparently, neither he nor others in his party realized that 49 Waffen-SS soldiers were buried there. Sources said a junior White House aide did try to alert Deaver and others to the juxtaposition of events they now faced: Reagan had shunned a concentration camp but would lay a wreath at the German military cemetery where soldiers who fought for the Nazis were buried.

On April 11, Speakes announced Reagan's itinerary, including the Bitburg cemetery stop. (Speakes that day said he did not know whether Americans were buried there; later in the same briefing he was informed that it was only German war dead.) Speakes said the visit was designed to underscore post-World War II reconciliation.

"Larry, he's paying homage, apparently, to the defenders of the Third Reich, while ignoring the victims of the Third Reich?" asked reporter Myron S. Waldman of Newsday. "Is there any way to directly address that?"

Speakes responded: "I've said what I'm going to say. He's spoken on it. I've spoken on it. Enough said."

A firestorm of protests followed from Jewish and veterans organizations. Speakes and chief of staff Regan watched the network broadcasts that night in their hotel room in Santa Barbara. Both expected heavy coverage of the announcement, focusing on Bitburg. They were surprised that only one network (CBS) made a full-scale report on the decision.

As protests mounted the next day, Regan talked by telephone with the president at his ranch, officials said. They concluded that the White House response should be to emphasize Reagan's activities in the United States commemorating the Holocaust, including his plan to award author Elie Wiesel the Congressional Gold Medal.

But this strategy didn't slow the protests. After returning to Washington, Reagan agreed, in response to the outcry, to visit a Nazi concentration camp site. His aides hoped this would quell the furor. Deaver was sent back to West Germany to find a suitable location. He settled on the Bergen-Belsen death camp site.

By this time, reporters had identified SS graves at Bitburg, and the West German government apparently notified the White House of this fact. The White House asked the German government if perhaps the itinerary could be changed, but Kohl resisted.

On April 18, Reagan expressed the view that the Nazi soldiers buried at Bitburg "were victims, just as surely as the victims in the concentration camps." The next day the president awarded the medal to Wiesel, who used the occasion to plead with him to cancel the Bitburg visit.

But the White House rejected Wiesel's plea. In a telephone call, Reagan assured Kohl that he would go ahead with the Bitburg visit. White House officials began a desperate search for ways to take the sting out of the Bitburg visit by shortening it, surrounding it with more dramatic events, and possibly abandoning the wreath-laying.

Neither continuing protests from many Americans nor resolutions passed by both houses of Congress deterred the administration, setting the stage for the visit to Germany that begins today.