PHOENIX, FEB. 26 -- Arizona's Supreme Court refused to delay the start of Gov. Evan Mecham's impeachment trial on Monday but did not rule out blocking the proceedings later.

The ruling came in an emergen- cy session during which the gov- ernor's lawyers cited danger to

his constitutional rights and

the justices expressed concern about breaching the separation

of judicial and legislative pow- ers.

The high court said it would decide Tuesday -- one day after the Senate trial is to begin -- whether

to issue an injunction against

it.

Thomas Crowe, an attorney for the first-term Republican, had told the high court in seeking the delay that Mecham's rights would be violated if an impeachment trial were held before related criminal charges were heard in court.

The Arizona Civil Liberties Union filed a brief arguing that Mecham's right to a fair criminal trial on charges of concealing a $350,000 campaign loan would be violated if the Senate proceeding were held first.

In another development, Mecham's chief attorney, Murray Miller, withdrew from the case and said Washington attorney Jerris Leonard has taken charge of the defense.

Mecham was impeached Feb. 5 and, several days later, the House approved 23 impeachment articles outlining details of three broad charges: concealing a $350,000 loan to his 1986 campaign; mis- using $80,000 from the governor's protocol fund by lending it to

his auto dealership, and trying

to thwart investigation of an al- leged death threat by a state official.