The first is the United States. Trump is unpredictable; with his election victory, American politics are now even more so. Admittedly, the Republicans hold both the White House and Congress, but, to put it mildly, not every Republican is a Trump supporter. The skepticism is especially marked when it comes to Russia — witness the calls for an investigation into Russian interference in the election.
In short, Trump may well seem like a pliable ally to the Kremlin, but American politics are much bigger and more complicated than Trump. The balance of power in Washington has yet to be decided, and relations with Moscow may prove one of the major fault lines.