The campaign against the Democratic leader comes as his job approval ratings are soaring, defying the gravity of the charges of sexual misconduct, perjury, and obstruction of justice against the President.

With few exceptions, Republicans in Congress were initially quiet in the face of allegations that Clinton had an affair with ex-White House intern Monica Lewinsky, lied about it under oath and urged her to do the same.

But now Newt Gingrich, Speaker of the House of Representatives, and his lieutenants Dick Armey and Tom DeLay, are firing pointed criticism aimed at puncturing the President's buoyant standing in the polls.

The Republicans have shied from levelling charges of sexual misconduct against Clinton, focusing instead on allegations of obstruction of justice in the face of probesby Congress and independent prosecutor Kenneth Starr.The renewed attacks can partly be explained by increased Republican frustration that sordid and serious allegations have not dented Clinton's popularity.

But the strategy also owes much to the Republican's need to energize the party's activist base for the campaign ahead of the November legislative vote, according to Stephen Hess, political scientist at the Brookings Institution.

``In an off-year election, the major factor in winning is turnout as only a third of registered voters actually take part,'' said Hess, adding ``if you don't get your base support out, you're going to lose.''

The Republican base is dominated by ``fundamentalist Christian groups whose members are offended by the attitudes and character of the President,'' and so respond well to such criticism, said Hess.