RIGHT now the 1988 presidential race can be described as two largely undifferentiated clumps of candidates. The Democratic cluster has Rep. Richard Gephardt, Gov. Michael Dukakis, and Sen. Paul Simon rounding out the top of the cluster, at least in the first delegate contest state, Iowa, but only minimally ahead of Sen. Joseph Biden, Sen. Albert Gore, the Rev. Jesse Jackson, former Gov. Bruce Babbitt, and a potential candidate, Rep. Patricia Schroeder. The Republican cluster has a threesome of Vice-President George Bush, Sen. Robert Dole, and Rep. Jack Kemp among the ``most likely to succeed,'' ahead of Gov. Pierre duPont, former Secretary of State Alexander Haig, and the Rev. Pat Robertson.
But these clusters have not really begun to split in any significant way.
For both party's races, today's start of the Senate hearings on the nomination of Robert Bork to the Supreme Court could begin to produce the initial meaningful separation among the candidates.
The hearings are, of course, important, first in terms of the court's composition itself, apart from any bearing on the election. On subjects from women's rights to whether the legislature or the courts should take the lead on making new law, Mr. Bork needs to be heard before a confirmation vote can be taken.
Senator Biden, as the judiciary committee chairman, will share the spotlight. Mr. Biden's biggest risk is to come across as emotionally antagonistic - as injudicious. If the hearings run smoothly, win or lose on the vote, Biden could show a temperament of leadership potential.
The hearings could prove even more important on the GOP side. Senator Dole, as minority leader, is handling the Bork nomination. A Bork victory would enhance Mr. Dole's claim that he, more than Vice-President Bush, has fought President Reagan's battles on Capitol Hill.
If an arms control agreement on mid-range missiles is reached by President Reagan and Mikhail Gorbachev, the topic of today's White House meeting with Soviet Foreign Minister Eduard Shevardnadze, again it will be up to Dole to see the measure through Senate ratification.
Meanwhile, Mr. Bush will shortly head off on a 10-day, six-nation tour of European capitals, ostensibly on behalf of President Reagan. This could add to the grist of Dole's claim that the senator dutifully labored in the political vineyard for the President while the vice-president basked in distant limelights.
Running for president is arduous. Judgments can be swift and harsh - witness the jettisoning of Gary Hart from the race. Biden has already been criticized for intemperate remarks to the secretary of state, and for cribbing a campaign speech from British politician Neil Kinnock. Dole's sharp tongue is remembered from his 1976 race alongside Gerald Ford, and his current campaign organization is said to suffer from Dole's wanting to do everything himself.
Still, it is fair that would-be presidents be tested by issues of the highest order, such as the Bork nomination.