Bill Clinton cannot run again because of the 22nd Amendment to the Constitution of the United States, which prohibits a president from serving more than two terms in office.
Even though nobody seriously backs Al Gore, his stock went up recently because the impeachment scandal eliminated almost all other possible Democratic contenders.
But the Republicans are far worse off. The Republicans in the House and Senate have cut their own throats and it is unlikely that any of them will ever be elected to higher office again. Some of them will be re-elected to their present offices, but many will quietly resign or not run again. The Republican Party will need to find new candidates to field in the coming elections.
Several prominent Republicans saw that the impeachment effort was doomed to failure and wisely refused to commit themselves one way or the other. Included are the Bush brothers, now both state governors, either of whom is likely to be a presidential candidate. Also, notably, New York's fascist Mayor Rudy Giuliani and New York Governor George Pataki are now saying that they opposed impeachment all along, but they were somewhat muted in their comments when the matter was pending before Congress.
In short, the Democrats now have nobody but Hillary. The Republicans now have nobody but Bush. So, it looks like there could be a repeat of the Clinton-Bush election of 1992, only with the first names changed.
Hillary Clinton has a major strike against her. She is perceived as being a left wing liberal, especially in view of her failed Health Care Reform. She is not as far to the left as Dirty Commie Rat Al Gore, but her image does suffer in this regard. In addition, nobody would vote for her as the wife of Bill Clinton. Everybody realizes that her husband would have little influence over her policies and decisions, if she is elected.