No American should be mistaken. The possibility of President Clinton's being forced to leave office is now real.

Whether or not you believe this should be the situation, whether or not you believe it is justified, it is a reality.Washington is now a cauldron, steaming and bubbling with the heat of this reality.

Republican and Democratic party leaders are in the process of deciding whether they would rather have Bill Clinton or Al Gore as president.

They get to decide because most of them are in Congress. And the ones who aren't, finance those who are. That is, they bankroll congressional campaigns and therefore have heavy influence.

The Constitution gives Congress the power to remove a president through impeachment, and President Clinton by word and deed has opened the possibility of impeachment. And Kenneth Starr has pursued the opening.

There are three basic avenues being discussed behind closed doors on both sides in the decision-making corridors of Washington.

One: The House of Representatives votes for an impeachment trial, the Senate conducts the trial, decides the president must give up his office, and he does.

Two: Public opinion, economic conditions, the mood of Congress and press coverage coalesce into a critical mass of disgust, disdain and dismay, creating so much pressure on the president and his family that he resigns.

In either of these instances, Gore becomes president. He then nominates a new vice president, whom Congress may accept or reject.

The third possibility: Congress, keying off public opinion and press coverage, decides the president should be reprimanded, but stops short of removal from office. Voting for an official censure would be the most probable such reprimand.

Deciding which of these three paths to follow figures to be a long, drawn-out process. That is, unless the president suddenly decides to throw in the towel and quit. While that IS a possibility, by any reasonable analysis it ignores the history of the Clintons, and is not at the moment considered very likely.

More likely is that the president and the first lady fight tenaciously for delay and a chance to hold on long enough for him to finish his term. But they are limited in what they can do.

Their best hopes are that Clinton's job approval rating stays up in the polls, that the economy, especially the stock markets, weathers current uncertainties, and that Democratic candidates do better than expected in this November's elections.

In private, Republican leaders are increasingly reaching the conclusion that they can get Clinton out of office if they choose to do so. Whether that would be good or bad for their chances of regaining the White House in 2000 is a question still hotly debated.

Some Republicans think that by ensuring Al Gore is the incumbent next time, and likely Democratic nominee, they can give the future Republican nominee the best chance.

Democrats must come at this question differently. Gore, succeeding the president before Clinton's second term is over, would give their party a change at the top and a fresh start. But Gore's weaknesses - his dullness as a speaker and campaigner, his problems with money-raising laws in the last campaign, and his long association with the Clintons - are worrisome to party leaders.

So, to Gore or not to Gore. That is the question on both sides of the congressional aisle, whether or not any of the decision makers choose to put it so bluntly.

The days and weeks of September are going to be tougher, rougher and nastier than most Americans could have expected when the now fading summer began.