The only counter to that argument is that Trump is virtually un-blackmailable to his rusted on supporters - they're too stupid and uninterested in ethics to care about Putin. Conservatives both in America and here think he's cool because he's down on Muslims and gays - he's a tough man who get things done - they're not going to dump Trump even if they knew Trump personally had secret contact with Putin and was lying about it. They would just say "Obama and Hillary did just as bad."
As for Jason Soon's (hi there) cavalier attitude to Russia, Putin and (apparently) political murder - here's a couple of things for him to consider (apart from psychoanalysis to make sure there really is no subconscious Putin man-crush going on there)
* a couple of articles, such as this one, have noted that for a few years now, RT has developed a very friendly attitude to American libertarians. Not hard to see the Kremlin's interest there, if libertarians are true to their American isolationist views.
* Reason, on the other hand, has a recent article "Russia's Global Anti-Libertarian Crusade" making the very reasonable argument that Putin's geo-political interests and philosophy are certainly against libertarian, liberal, principles on how governments should conduct themselves, and gives recent examples of Russian interference in the Balkans, etc.
Here are two key paragraphs:
One of the surreal twists of the past year in American politics has been the rapid realignment in attitudes toward Russia. Democrats, many of whom believe that Russian interference was key to Donald Trump's unexpected victory last November, are now the ones sounding the alarm about the Russian threat. Meanwhile, quite a few Republicans—previously the keepers of the anti-Kremlin Cold War flame—have taken to praising President Vladimir Putin as a strong leader and Moscow as an ally against radical Islam. A CNN/ORC poll in late April found that 56 percent of Republicans see Russia as either "friendly" or "an ally," up from 14 percent in 2014. Over the same period, Putin's favorable rating from Republicans in the Economist/YouGov poll went from 10 percent to a startling 37 percent.and:
Nonetheless, there is a real Russian effort to counter American—plus NATO and E.U.—influence by supporting authoritarian nationalist movements and groups, such as Le Pen's National Front, Hungary's quasi-fascist Jobbik Party, and Greece's neo-Nazi Golden Dawn. Today's Russia is no longer just a moderately authoritarian corrupt regime trying to maintain its regional influence. Cloaked in the mantle of religious and nationalist values, the Kremlin positions itself as a defender of tradition and sovereignty against the godless progressivism and the migrant hordes overtaking the West. It has a global propaganda machine and a network of political operatives dedicated to cultivating far-right and sometimes far-left groups in Europe and elsewhere.