A weakened President Bill Clinton begins a summit today with Russian President Boris Yeltsin, whose government is falling further into chaos by the day. Given their circumstances and the fact that it is too late to simply call off their meeting, they should instead scrap whatever agreements they had approved, talk generally, enjoy each other’s company and hope for better days.

Like most summits, this one is likely to be scripted to the minute: The impromptu backslapping, the heartfelt toasts, the presidents’ somber faces after a lengthy private talk, the Momentous Agreement announced at a joint press conference, then a quick version of the buddies routine before waving good-bye. Unfortunately this time, there also are important issues on the table — from the sale of missile technology, to the situation in North Korea to anti-terrorism efforts, to — most importantly for President Yeltsin — the Russian economy.

Until approximately a week ago, it would have been possible to rationally discuss these challenges and outline ways in which the two former enemies could work together. But the overwhelming defeat of Mr. Yeltsin’s acting prime minister, Viktor Chernomyrdin, and the further demands from parliament that the president himself resign changes this. No agreement with President Yeltsin is advisable now because he has no authority to carry one out.

President Clinton’s difficulty this week will be to resist temptation. To help Americans forget about his troubles with special investigator Kenneth Starr, he needs to look like a world leader. What better way than to trade support for Mr. Yeltsin in exchange for promises on weapons reductions or agreement on policies in the former Yugoslavia?

The problem with such promises is that the person making them no longer has control of his political future. President Yeltsin is negotiating furiously with opponents to keep his job. Anything he signs is subject to review and rejection — witness the power-sharing agreement he thought he had with the Communist parliament.

Rather than add disappointment and cynicism to the U.S.-Russian relationship, the two leaders would do better to put the important stuff on hold and talk about anything else — the price of vodka, baseball’s homerun-record chase, the latest from Mikhail Gorbachev — anything but matters of substance. That means surrendering the scripted world-shaking end-of-summit press conference, an omission for which both will likely be grateful when they return to face their respective legislatures.