PHOENIX, FEB. 28 -- The hoteliers in this broad, dry valley fretted last year about boycotts, but this week the town is awash in conventions and rooms are scarce. The recall-the-governor petitions no longer clutter supermarket doorways.

The irrepressible governor of the state, Evan Mecham, is at least temporarily out of office pending his impeachment trial, and a less outspoken white-haired Democrat is in charge.

Yet no one seems able to relax and appreciate the changed circumstances, for Mecham is still at large, and his trial by the state Senate for removal from office is scheduled to begin Monday, although he said he would try to halt it through last-minute federal court action.

No governor in American history has fallen into so much political and legal trouble from so many sources so early in his term. Mecham faces three crucial challenges to his future -- this Senate chamber proceeding, a March 22 criminal trial on charges of failing to report a $350,000 campaign loan, and a May 17 recall election.

He marshals his forces in his temporary office in suburban Glendale. He was impeached, and forced to relinquish his office to Secretary of State and acting Gov. Rose Mofford, by a 46-to-14 vote of the state House Feb. 5. Twenty-five of the votes against him came from fellow Republicans.

His party's leaders, fearful of a voter backlash against the entire GOP ticket, would prefer that Mecham quietly return to his former lucrative life selling cars. But that is not Mecham's way.

It took the 63-year-old former one-term state senator and perennial candidate five tries to become governor. On Saturday he scorned rumors he would resign and lacerated the Senate for refusing to delay its trial until his criminal case had run its course. "To resign would be to give in to the powers who have schemed and planned against me," he said.

To some minds, the story of Mecham's election and 14 months as governor provides one of the strongest arguments ever for the two-party system. He won in November 1986 with only 40 percent of the vote. Democrat Carolyn Warner (34 percent) and Democrat-turned-independent Bill Schulz (26 percent) appeared to split the anti-Mecham vote. Although some analysts think he would still have won a two-person contest, the chances of his reaching the governor's mansion, and inspiring this legal and political mess, would have been much less.

Mecham's slide into political infamy began shortly after his inauguration when he canceled the state holiday honoring the Rev. Martin Luther King Jr. on the grounds that the previous governor, Bruce Babbitt, a Democrat, had acted illegally in declaring it. The move produced demonstrations and convention boycotts.

He defended a book that used the term "pickaninny" for blacks. A Mormon, he told a Jewish synagogue breakfast that the United States "is a great Christian nation."

The state attorney general uncovered evidence of his unreported campaign loan, which led to the indictment of him and his brother on charges of fraud and perjury. The House bill of impeachment charged him in addition with improperly investing $80,000 from a private governor's fund in his family's auto dealership and interfering in the investigation of an alleged death threat by a state official.

The last U.S. governor recalled was Lynn Frazier of North Dakota in 1921. Gov. Huey Long of Louisiana was impeached in 1929, but the charges were later dropped. More recent Govs. Otto Kerner (D) of Illinois and Ray Blanton (D) of Tennessee were convicted of corrupt practices, but only after they had completed their terms.