“He’s not compromising,” warned Fiona Hill, the Brookings Institution’s ace Putinologist. “He’s looking for what the market will bear. He’s trying to see how much of Ukraine he can take, and he’ll settle for what he can get.”

Does that mean additional military action? Not if Putin can get what he wants without it. In the short run, Hill and others say, Russia will continue to press for Ukrainian constitutional reforms that would give pro-Russia areas more autonomy and, if Moscow has its way, the right to secede. And Russia wants a delay in Ukraine’s presidential election scheduled for May 25, because the vote would make Kiev’s current provisional government much more legitimate in the eyes of the world.

“He may not need to invade to get what he wants,” Hill told me. “He knows that if he doesn’t take military action, we’ll all say, ‘Thank God.'”

In that sense, Secretary of State John F. Kerry was mistaken a few weeks ago when he denounced Putin for behaving like a 19th century autocrat. Instead, the Russian president is a product of the 20th century KGB, where his career began. He knows that subversion is much cheaper than invasion.