As a result of this myopia, Trump refuses to address the possibility that Russia, or another country, might try to meddle in future elections and, thus, will not hold a cabinet meeting on the subject. This, in effect, becomes an open invitation for other countries to interfere in our elections. Indeed, the 2017 special elections saw a massive uptick in Russian bots disseminating millions of pro-Trump messaging in an attempt to influence voters.
Because Trump is so averse to hearing anything bad about Russia, the subject of Russia or the deeply corrupt Putin aren't even mentioned in intelligence briefings for the President, no matter how serious the threat. These matters are included in written information given to Trump, which he either doesn't read or chooses to ignore.
Accordingly, the United States is highly vulnerable to any kind of nefarious activity that Russia but attempt, whether it be hacking, industrial espionage, or old-fashioned spying.
One could wonder if Trump is some kind of Manchurian Candidate controlled by Russia. After all, Trump started traveling to the Soviet Union in the 1980s when few other Americans tried to do business there.
I suspect a more realistic scenario grounded in psychology: any acknowledgment by Trump that Putin and Russia monkeyed in his election delegitimizes him, so his emotional fragility causes him to avoid the subject altogether.
All his other failings aside, this Russian problem alone demonstrates how unfit Trump is to serve as President. All the more troubling, the GOP will largely turn a blind eye and allow him to continue.