" With or without his senior advisers, this was the moment for Trump to make the American interest clear—namely, that the Kremlin’s hacking of the election amounted to ill-considered interference. And that any attempt by Moscow to do the same in 2018 or 2020 would lead to a stringent U.S. response—more sanctions, travel bans, even a cutoff of Russia’s access to the SWIFT banking payments system. Putin would interpret anything less than this as American weakness. And, practically, a green light for his operatives to tamper again in Washington’s affairs. All done, of course, under the same cover of plausible deniability. There was no official hacking, the government wasn’t involved, et cetera. Apparently, Trump said none of this. "

― Luke Harding , Collusion: Secret Meetings, Dirty Money, and How Russia Helped Donald Trump Win