This is a tough one. As more information continues to come out about the extent of the links between Trump, his people, and Russia, Trump is in a bind. He wants to lift sanctions on Russia. Can he? It depends. Let's go through the possibilities.
Case 1) Trump really is being blackmailed.
Yes, we have to consider this. If Putin really does control Trump, then nothing that gets leaked to the press matters. No matter how bad Trump looks, he still has to do Putin's bidding. Trump will hate it because it will show how weak he is, but he's just fucked.
Case 2) Trump is all bluster
If Trump is nothing but a pompous windbag impressed with his own self-importance, then he flips on Russia and starts getting confrontational. He needs to show how big his... hands are, and that means demonstrating that he isn't Putin's puppet. That means flipping. Since Trump has no real commitment to any policies, it won't matter to him if he is inconsistent. He recently made a few statements about Crimea that seemed to indicate some possible movement in this direction, but we'll see if this gets backed up.
Case 3) Trump is just in love with Putin
The complication is that Trump makes a lot of statements indicating sincere, deeply felt, sexual attraction to Vlady. Trump loves nothing more than an authoritarian leader who understands the Conan rule.
The problem here is that if Trump is just infatuated with Vlady the Barbarian, then nothing changes. Even if his continued toadying to Putin makes him look like he is being controlled, he'll still do it because he can't take his eyes off of those pecks.
You begin to see the problem, then. Distinguishing between Case 1 and Case 3 is difficult. Trump's behavior, in either case, would be the same.
A while back, I wrote that even if Putin had blackmail material, it probably wouldn't matter. Everything about Trump indicates that Case 3 is probably true, even if Case 1 is also true. They aren't mutually exclusive.
The real question is whether or not we see a change in behavior indicating Case 2.