Russia - what does Putin hold over Donald Trump? Helsinki echo

Opinion letter echo published in the Florida newspaper the Palm Beach Post~

Donald Trump abandoned American patriotism and displayed incompetent leadership when he kowtowed to Vladimir Putin at the Helsinki summit.

On July 16, 2018, about the failed Helsinki summit

Letter to the editor:

I watched, along with millions of others, as Donald Trump, the president of the United States openly and shamefully sided with Vladimir Putin, the president of the Russian Federation, in denying their involvement in hacking, theft, and undermining of our American 2016 election process.

You don’t need to be a Democrat or Republican to recognize what transpired there. Our special counsel, Robert Mueller, a lifelong Republican, indicted with amazing and precise detail 12 military intelligence agents of Russia, who have obviously been under the direct control of Vladimir Putin.

Putin not only undermined our 2016 elections, but he also made similar efforts throughout Europe. We are only now beginning to understand and appreciate the scope of his efforts to undermine democracies in Europe and build up the forces of racial nationalism.

Furthermore, Dan Coates, director of national intelligence, has raised alarm about Russia's continuing efforts in 2018. Reasonable people will agree that Russia is emboldened when the strength of America's alliances with NATO is diminished and weakened. Russia is strengthened when we in the U.S. are divided and unable to even agree to the facts before us. From Tobias Raye, Boca Raton

MaineWriter postscript- what does Vladimir Putin hold over Donald Trump that would enable him to abandon his allegiance to American intelligence agencies and put US national security at risk of being subservient to the Russian dictator?