Russian troops are encircling Ukraine from three sides. In Washington and Brussels, there are warnings of crushing sanctions if Russian President Vladimir Putin orders an invasion. Embassy families — both American and Russian — are being evacuated from Kyiv.

Yet there are still diplomatic options — "off-ramps” in the lingo of the negotiators — and in the next several days U.S. President Joe Biden's administration and NATO are expected to respond, in writing, to Putin’s far-reaching demands.

The question is whether there is real potential for compromise in three distinct areas: Russia’s demand for ironclad assurances that Ukraine won’t enter NATO; that NATO won’t further expand; and that Russia can somehow restore some approximation of its sphere of influence in the region to before the strategic map of Europe was redrawn in the mid-1990s.