Should Mikhail Gorbachev run for president? This question, long more of a foible for the last Soviet president's many admirers to toy with than a serious proposition, suddenly appears to have gained currency this week as he has stepped back onto Russia's political stage.The logic for Gorbachev's timing seems clear. First, the popularity of his old rival, Boris Yeltsin, is waning. And second, Gorbachev only ever stands a chance of success if he runs for the leadership of something broader than Russia. With nostalgia for the Soviet Union fast growing, that may now seem possible to him.In terms of age, also, Gorbachev remains fully in the running. He is a few months younger than Yeltsin and, in appearance at least, seems healthier.But, in case he should have any delusions, Gorbachev should understand that he has a long way to go before assembling even a dark horse's chance of electoral success.His chief problem is that Russians hankering for the past remember Gorbachev not as an advocate of the Soviet Union, but as its destroyer. A close second is that Russians are presently looking for solutions to their economic woes. Gorbachev, over the five years or more of perestroika, already proved to them that he had none.No less a hurdle is that for a politician with one of the world's most impressive resumes, Gorbachev lacks a vital test of experience -- he is an electoral virgin. The man who broke the back of Soviet repression has never stood for democratic election. Who knows if he has what it takes to win at the polls.If that sounds trivial, think of Yegor Gaidar, another politician of no small stature who attracted popularity in the West, but proved an unmitigated disaster when facing voters.But perhaps the tastiest food for thought in considering a Gorbachev presidential campaign is also the most fundamental. It is extraordinary that he can even consider such a move.Gorbachev, if he chose to run in 1996, would be the first ex-Soviet leader ever to get a second chance. He is neither dead nor living in fearful exile. On the contrary, he lives in Moscow, travels as a voluble citizen of the world and feels free to call Yeltsin a "traitor."Gorbachev's friends should advise him to accept his well-earned place as one of the world's great elder statesmen and leave the government of Russia to a new generation of leaders. His chances for success are minimal. We, however, would like to see him try. If Gorbachev were to declare himself for the elections due in 1996 and compete for the post he only ever held by appointment, it would show great courage on his part and contain an irresistible element of poetic justice.