This graph says it all:

Republican opinion on Putin seems to have moved not because Trump is pro-Russia or because there’s suddenly an opportunity for better relations with Moscow. It moved because Russia interfered in the election to the Democrats’ detriment, whether that was the core motive or not. That’s the point we’ve reached in partisan polarization, apparently. Want better relations with the U.S.? Then do what you can, legal or not, to make the eventual winning party’s path to electoral victory easier.

To put that another way, the surge in favorability among Republicans for a Russian fascist and kleptocrat who’s used anti-American propaganda relentlessly to consolidate power at home may be a more or less straightforward byproduct of partisan politics.

If widespread murder helped Republicans win political offices,.Republican voters would start favoring widespread murder.