REAGAN and Chernenko should meet. The United States political calendar shows an opening for a superpowers leadership session in late summer. This is in August, the time of the Republican National Convention and before the Labor Day start of the fall election campaign. If it takes four or five months to plan such a meeting, there is just time enough to do so.
The Democratic contenders have said they would seek such a get-together if elected. By working on at least the intention to stage a summit, even with a limited agenda, President Reagan would partly neutralize the Democrats' political argument that they are willing to risk disappointment to show their earnestness in pursuit of peace. Why should the Republican incumbent give the Democrats that argument?
Of course there would be charges of cynically using a summit for reelection, just as the President's trip to China this spring, then his visit to his forebears' home in Ireland when he attends the Western economic summit in London in June, will be criticized for their obvious political utility. But such are the advantages of incumbency.
If President Reagan is sincere about his administration's readiness to return to the arms negotiating table, it seems only consistent for him to be ready to meet with the new Soviet leader, Konstantin U. Chernenko, to talk about US-Soviet interests generally. What is there to lose besides some degree of ignorance of the other's character, style, priorities, and arguments?
Mr. Chernenko might not want to meet, of course, at least not until after it is clear whether Mr. Reagan will be returned to office.
But a preelection session with Reagan - or at least a signaled willingness to meet - could be worth more in Soviet chips than a later agreement with a reelected Reagan. And Chernenko could always schedule another summit session in 1985 if a Democrat is elected.
Chernenko is getting a fast, visible buildup in Soviet society; a Reagan summit could reinforce the image of a Soviet leader in charge, an image that flagged during Yuri Andropov's long illness.
On Washington's part, there is a short list of diplomatic ventures that would give justification enough for a get-together: confidence-building measures like notice of military maneuvers in Europe; an upgraded hot-line pact; expanded cultural and other exchanges; acting on consulate plans for New York and Kiev; air navigation steps to reduce likelihood of another civilian jetliner incident like last September's in the Pacific; and so forth.
Even a tentative proposal for getting arms talks, interrupted since last fall , back on track would be enough of an announcement to suggest the start of a more constructive dialogue.
No one should get up false hopes about whether a summit will soon be held or what it might accomplish. The Reagan administration itself remains divided over the issue.
Some administration players worry that the US usually gives away too much, just for the opportunity to meet or to reach an agreement at all.
Others feel the administration will soon have gone too long, four years, without a face-to-face session with its chief adversary, that Mr. Reagan might gain a different sense of US global responsibilities from such a meeting, and that it would ease US relations with European allies. Politically, the overriding foreign policy issue for the White House is the President's ability to manage US relations abroad.
Both the White House and the Kremlin are now sizing up the other side's receptivity to a summit.
With the obvious caveat that there must be something serious to discuss, the US signal should be ''Yes, let's meet.''