US political ins and outs

In the United States, as well as in Canada, suddenly it is a time for bowing out. Best-known of those exiting is Speaker of the House Thomas P. (Tip) O'Neill. He says he'll retire from Congress in no more than three years, and that if a Democrat wins the presidency this year he'd like to be named ambassador to Ireland ''or someplace like that.''

A much-caricatured bear of a man who is a throwback to the age of Irish-dominated urban politics, he long has been known for his concern for the poor and disadvantaged in society. Tip has been in Congress 31 years: Washington won't be the same without him.

Neither will the Democratic presidential race be the same without the three candidates now withdrawing. Between them they offered Democratic primary voters a wide range of choices.

First to fold his campaign tent was Sen. Alan Cranston, the dogged Californian who pushed all candidates on the issue of nuclear disarmament by making that the centerpiece of his effort.

Next came Sen. Ernest F. Hollings, the witty South Carolinian who had sought to duplicate Jimmy Carter's move from Southern political prominence to his party's presidential nomination. On some issues, such as defense and deficits, he took more conservative positions than several candidates. So, too, has former Florida Gov. Reubin Askew, who also decided to pull out of the race after having finished last in the New Hampshire balloting.

But among those now bowing out the spotlight shines primarily on Tip O'Neill, who in 1977 succeeded as speaker of the House of Representatives a man as diminutive (Carl Albert) as O'Neill is huge. As speaker, O'Neill has had his ups and downs; for the past three years, since the Senate became Republican-controlled, he has been the Democrats' principal voice in the nation's capital. In that role he has often roared with the bluff voice of an old-time Irish politician at the Republican leader, President Reagan, who often takes note of his own Irish heritage. Despite their sometimes sharp policy disagreements the two men seemed genuinely to like each other.

The role of House speaker has changed enormously since the back-patting ''go along to get along'' days of Sam Rayburn, speaker during the 1940s and '50s when party discipline was strong and a need for negotiation with party members was nonexistent.

As more of Congress's business has been conducted in the open over the past 20 years, much of the leaders' most important work has been persuasion and negotiation, both within their own party and with leaders of the other party. It is taxing, thankless, and seemingly endless work.

But that is what will face the eventual O'Neill successor, whether it is a virtual newcomer or someone already in or near the leadership - like second-in-command Jim Wright, the heir apparent; the analytical Thomas Foley, now majority whip; or Dan Rostenkowski, Ways and Means Committee chairman.

And the House members they will preside over, whether as House speaker or as minority leader, will differ from O'Neill's oldtime urban and rural colleagues, often colorful and rumpled, and occasionally known to scurry onto the House floor wanting to vote the party way but not knowing what it was. In those cases one of their party's doorkeepers would furnish quick instruction: thumbs up (vote yes) or thumbs down (no).

Today's House members increasingly are blow-dried politicians used to performing smoothly before the television camera. And they're independent in thought, whose votes are guided by negotiation rather than doorkeeper instruction.