security council senior director for european and russian affairs. but she is perhaps best known for her testimony during the first trump impeachment on his efforts to strong-arm ukraine's president into helping him win re-election. fiona hill is also the author, by the way, of a very important book "there is nothing for you here: finding opportunity in the 21st century." fiona, thanks so much for joining us. you hear president biden's vow to unleash what he says would be unprecedented sanctions, economic sanctions, diplomatic sanctions against putin's government if russia invades ukraine. is that going to be enough to deter putin, in your view? because you also heard the president rule out, at least for now, direct u.s. military action. >> well, it really, wolf, depends on how this is structured. it certainly won't be enough if it's just the united states taking action. so i think what's significant