Decision time for some Democrats. They must join '88 race for presidency soon or give up

To run, or not to run - that is the question. A half-dozen Democrats, pushed by friends and supporters, are under mounting pressure to decide quickly whether to battle for the White House in 1988.

Experts say the time for Hamlet-like delay is over. The 1988 campaign has begun in earnest. Further postponement could ensure the ``slings and arrows of outrageous fortune.''

The next few weeks are expected to bring announcements - yea or nay - from Gov. Mario Cuomo of New York, Sen. Sam Nunn of Georgia, Sen. Dale Bumpers of Arkansas, and Gov. Michael Dukakis of Massachusetts.

Sen. Joseph Biden Jr. appears set to run, with an announcement in May or June.

Sen. Paul Simon of Illinois may run if Senator Bumpers opts out.

They would join a field that is almost sure to include former Sen. Gary Hart of Colorado, former Gov. Bruce Babbitt of Arizona, the Rev. Jesse Jackson, and US Rep. Richard Gephardt of Missouri.

The Democratic prize looks worth the effort. For the first time in 18 months, the Gallup Organization reported this week that the leading Democrat, Senator Hart, now tops the leading Republican, Vice-President George Bush, as the popular choice for 1988.

In the latest trial heat, Hart leads Mr. Bush 51 to 38, with 11 percent undecided. Bush whipped Hart in all five trial runs last year.

Time now becomes a crucial factor for all Democratic contenders, although time is more crucial to some than others.

Political analyst Richard Scammon explains that the Democratic field can essentially be divided into two broad groups. One consists of Messrs. Hart, Cuomo, Nunn, and Jackson, all of whom have large, natural bases of voter support. They, perhaps, can move a little slower.

The others do not have broad bases of support. They must get started quickly, make an impressive showing in either Iowa or New Hampshire, the kickoff states, then depend on their momentum to carry them through the other primaries, says Mr. Scammon, who is director of the Elections Research Center in Washington, D.C.

Hart's base, scattered across the country, remains significantly large from his 1984 campaign.

Cuomo's base lies along the East Coast, especially in New York State. Nunn's base is the South.

And Jackson's base rests with black voters, who make up a key share of the Democratic electorate.

All the other candidates are starting from scratch. Some get only an asterisk (denoting less than 1 percent) in the polls.

Some, like Governor Babbitt, are known to fewer than 1 out of 5 Americans. They must organize, raise money, and get their names and faces in the newspapers and on television.

Among all the candidates, Hart remains the man to beat.

The former Colorado senator's backers were worried for a while. His support among Democratic voters had declined steadily throughout 1986, according to the Gallup Organization.

Hart was the first or second choice of 46 percent of all Democrats in January 1986; but that slipped to 40 percent in April, 34 percent in July, and 32 percent in October.

Then in January 1987 Hart popped back up to 53 percent, opening a wide gap with the Democrats' No. 2 choice, Chrysler president Lee Iacocca, who had 29 percent.

Mr. Iacocca now has accepted a new, four-year term as Chrysler president, however, and has filed for divorce from his new wife - two steps that have effectively taken his name out of the running.

A committee that had organized to draft Iacocca in 1988 is being disbanded.

Meanwhile, Cuomo's pace has picked up, and he is sounding more and more like a candidate.

His latest schedule includes trips to California and Florida (big money states) and New Hampshire and Iowa (key voting states) - the same itinerary others have followed to prepare for a presidential campaign.

The 1988 Democratic contest could become a Hart-Cuomo slugfest, but analysts are looking for at least one other name to emerge from the pack.

The reason: Neither Hart nor Cuomo comes from the South or represents traditional Southern thinking.

Yet the South could be pivotal in 1988. On a single day, ``Mega-Tuesday,'' March 8, 1988, a dozen Southern and border states will vote.

It will be the closest thing yet to a national primary, and it could put one candidate far, far ahead of the field.

Mega-Tuesday is ready made for a Southern candidate, such as Senator Nunn, or for a candidate who might appeal to the South, such as Representative Gephardt or Senator Biden.

Second of two articles. The first, on Republican candidates, appeared yesterday.