WASHINGTON, D.C.: Turning up the heat on a new wave of al legations of campaign finance improprieties on both sides of the aisle, Senate Republicans reversed course by agreeing to allow Senator Fred Thompson's campaign finance investigation to look into "soft money" donations. Fearing that any probe woul d wind up biting them as well, the GOP leadership had previously rammed through a deal that would limit Thompson to investigating only "illegal activities" that took place during the 1996 race. The Republican turnaround was spurred by the growing re alization that, while the White House fundraising scandal certainly looks like a mess, it is not clear whether laws were broken. If not, Thompson's committee would not touch the White House. According to Janet Reno's interpretation of the law, finance restrictions don't apply to the hundreds of millions of dollars in unregulated, soft money. Senate Majority Leader Trent Lott said there were arguments that under that interpretation, "some of these coffees, some of these sleepovers" at the White House might fall outside the scope of the investigation. Expanding the investigation may prove a tough pill for everyone in Congress. While Bill Clinton may have sold seats at his weekly radio address, each day is bringing new stories of si milar improprieties by Republicans as well. The party that raised Republicans who had raise $200 million more than the Democrats in the last election cycle has the Democrats on the griddle, but may not be able to avoid getting burned by the same inves tigative heat.