According to the basic mechanisms of arbitrary power exercise, after the expiration of his term at the top he could continue existing only on his successor's sufferance, and might be better off settling in Lukashenko's Belarus or in China. And such sufferance would not include the possibility of return to power.
The easing out of Yeltsin (and the so called slide away from democracy that some Russian detractors mention) came out of what Clinton did in Kosovo as Chechnya was also heating up.