Maryland Gov. William Donald Schaefer will be in Prince George's County tonight to consummate a marriage of political convenience, taking the first step toward building an alliance that could benefit the governor and the county's ambitious state's attorney, observers say.

Moreover, Schaefer's appearance at a reception initiated and arranged by State's Attorney Alex Williams will provide further evidence, if any was needed, of the growing political clout vested in Prince George's, a county Schaefer lost in last year's Democratic primary and one rapidly becoming indispensable to politicians at all levels.

The appearance marks Schaefer's biggest pitch to Prince George's County of his eight months in office, and Williams, the county's top black elected official, is delighted to catch it.

This new political alignment between Schaefer, who lost the county's black precincts badly in the primary, and Williams, who admits that his political aspirations go beyond the courthouse, can only benefit both men, county political observers said.

So it was of little surprise to hear that Schaefer almost immediately accepted Williams' offer to organize a reception for the governor.

"It should be good for Alex, good for the county and good for the governor," said Senate President Thomas V. Mike Miller Jr. (D-Prince George's).

Williams' move to set up the event and form an alliance with Schaefer was widely viewed within county political circles as a reflection of Williams' coming of age, underscoring his interest in life outside the criminal justice system.

"This is more than just a reassurance that Alex Williams can be reelected state's attorney," said Lance Billingsley, a politically active lawyer and adviser to County Executive Parris Glendening. "He does have further political ambitions."

The governor has made several other trips to Prince George's County since he took office. But this event is one of the largest involving Schaefer, with the Greenbelt Hilton expecting up to 500 people.

Williams, who said the event was his idea, insists that it is nothing more than an opportunity for Schaefer to become better acquainted with political and community leaders in the county. "There is no message I'm sending about a first step toward anything."

Whatever Williams' intentions, the event's planning exposed some political inexperience on two key fronts, political observers said. Neither Glendening nor Miller was aware of the event until after the date had been set.

As a result, Glendening initially said he would not attend the reception, citing a prior commitment with a visiting delegation from Senegal. And Miller, a key leader in the legislature, dismissed the reception as "not a big deal."

Williams said invitations to the reception were mailed to all of the county's public officials, community leaders and "movers and shakers." His failure to check on Glendening's availability, Williams said, was a communications mixup.

"Protocol says that he should have at least picked up the telephone and let Glendening know what was going on," said one county political activist, who asked not to be identified. "Alex did not have to get Parris' okay. It just would have been the courteous thing to do."

Miller said late last week that he had not received an invitation and was unsure whether he would attend the reception.

Glendening, whose support was one of several key factors in Williams' victory at the polls last year, eventually decided to attend the Schaefer reception after the two men discussed the event over lunch last week. Another topic during the lunch concerned rumors of Williams possibly running for county executive against Glendening. Those rumors were put to rest, a Glendening aide said.

Now Glendening will "make an appearance and at least wave his hand" at Schaefer's reception, said Tim Ayers, the county executive's spokesman.

Political observers said that Schaefer, who placed second behind then-Attorney General Stephen H. Sachs in Prince George's in last September's Democratic gubernatorial primary, probably has as much to gain from the reception as Williams. Schaefer lost the county overall to Sachs, 44 percent to 52 percent. But the governor took a larger beating in the county's predominantly black communities, losing some precincts by a 5-to-1 ratio.

During last year's primary campaign, Schaefer met with several of the county's black leaders, but the session was "less than harmonious," one of those leaders who attended the meeting said. State Sen. Decatur W. Trotter, a Schaefer supporter in last year's primary election, admitted the governor's relationship with the county's black officials has "not been completely rosy."

The budding alliance between Williams and Schaefer stands to benefit both men equally. But, when analyzed from the perspective of who has more to lose, the scale tips heavily on Williams' side.

"If only the {Democratic} party regulars show up, or if the turnout is low, that would make Alex seem to be less of a player in county politics," said a county political activist and Williams supporter.

Williams said Schaefer has not said anything to him about bolstering his black support in the county. "I hope he is not viewing this as a measure of how much power I have," Williams said. "This is simply an opportunity for people to come out, meet the governor and shake his hand."