ANYONE hoping for rough-and-tumble contests at the party conventions this summer is going to be disappointed. The Pennsylvania primary election on Tuesday eliminated just about any doubt as to who the likely presidential nominees will be: Vice-President George Bush for the Republicans and Massachusetts Gov. Michael Dukakis for the Democrats.
Jokes have abounded about the 1988 campaign being a contest among shades of beige. But what has happened is that voters made up their minds remarkably early on - in February and March - about whom to back. Hearts may not be on fire, but minds have been made up.
The vice-president, is of course, the heir apparent of the Republican Party. President Reagan has nominally kept hands off, but to those in Washington it has been no secret that Mr. Bush has been his clear choice to succeed him.
That Democratic voters have rallied so early around Michael Dukakis is particularly remarkable, given that the field was so large and so wide open. His almost preternatural serenity after his third-place finish in the Iowa caucuses in February now seems justified.
The support for both parties' leading men is broad among the rank and file. It is not the product of either man's television charisma or of party leaders' maneuvers to forestall nomination of an ``unelectable'' candidate.
Not that there aren't numbers of notable Democrats opposed to having Jesse Jackson on the ticket. But the view that party leaders are foisting Mr. Dukakis on the rank and file just because he's not Jackson is incorrect. Dukakis began winning lots of voter support when the anyone-but-Jesse contingent could have chosen from a broader field.
Meanwhile, the Rev. Mr. Jackson vows to continue his campaign through the June primaries. His poor showing in Pennsylvania, where Dukakis trounced him 2 to 1, was ascribed in part to difficulties with organization; he hopes to do better in Ohio and Indiana.
He and Dukakis are to be commended for keeping the campaign on a civil basis, with the emphasis on winning the White House rather than beating each other. Barbs and potshots may make good copy, but those who earlier mouthed off are now, be it noted, on the sidelines.
The main event for parties is November. Politicians have been willing to put up with a lot in the interest of furthering their party's chances in the general election. Even Bob Dole, not always the ideal of political good sportsmanship, made the point several times on the New Hampshire campaign trail that ``one of us Republicans will be the next president.''
Republicans see renewing their lease on the White House in 1988 as critical to consolidating and maintaining the gains of the Reagan years - control of the federal courts, for instance. Democrats, of course, see an equally pressing need to undo the Reagan years.
Both nominees-apparent are basically at the center of their respective parties. Those who have asked for a campaign about issues rather than personalities may find they get exactly that.