THOUSANDS OF MINNESOTANS HAVE CALLED OR WRITTEN TO THEIR CONGRESSIONAL REPRESENTATIVES IN RECENT WEEKS TO EXPRESS THEIR THOUGHTS ON WHETHER PRESIDENT CLINTON SHOULD BE IMPEACHED. SEVERAL STAFF MEMBERS ON CAPITOL HILL SAY THE IMPEACHMENT QUESTION HAS GENERATED A STRONGER CONSTITUENT RESPONSE THAN ANY OTHER ISSUE IN RECENT YEARS. MINNESOTA PUBLIC RADIO'S WILLIAM WILCOXEN HAS THIS REPORT... THIRD DISTRICT REPUBLICAN JIM RAMSTAD IS THE ONLY MINNESOTA REPRESENTATIVE WHO HAS NOT YET DECLARED HOW HE INTENDS TO VOTE ON IMPEACHMENT. BUT RAMSTAD'S INDECISION IS NOT FOR A LACK OF ADVICE. HIS CHIEF OF STAFF, DEAN PETERSON, SAYS STAFF MEMBERS ARE GETTING AN EARFUL...