Donald Trump has the most wealth of any past presidential candidate invested in Europe, and Putin controls Europe. This makes Trump the highest security risk ever presented or personally faced by a sitting president.
It is no secret that Putin has threatened European countries in the past and he holds too much power by way of his supply lines of fossil fuels.
From Wikipedia...'The Russian Federation supplies a significant volume of fossil fuels and is the largest exporter of oil and natural gas to the European Union. In 2007, the European Union imported from Russia 185 million tonnes of crude oil, which accounted for 32.6% of total oil import, and 100.7 million tonnes of oil equivalent of natural gas, which accounted 38.7% of total gas import....'
'In 2007, 38.7% of the European Union's natural gas total imports and 24.3% of consumed natural gas originated from Russia. As of 2009, Russian natural gas was delivered to Europe through 12 pipelines, of which three were direct pipelines (to Finland, Estonia and Latvia), four through Belarus (to Lithuania and Poland) and five through Ukraine (to Slovakia, Romania, Hungary and Poland). In 2011, an additional pipeline, Nord Stream (directly to Germany through the Baltic Sea), opened.'
'The largest importers of Russian gas in the European Union are Germany and Italy, accounting together for almost half of the EU gas imports from Russia. Other larger Russian gas importers (over 5 billion cubic meter per year) in the European Union are France, Hungary, Czech Republic, Poland, Austria and Slovakia. The largest non-EU importers of Russian natural gas are Ukraine, Turkey and Belarus.'
Trump could have billions invested across Europe and there is no way to stop the Russian strongman Putin from financially ruining Trump, so naturally Trump will succumb to Putin's threat to bankrupt him, and will become Putin's puppet in the White house, as Hillary predicted. Trump does not have the will to refuse Putin.
Trump does not have the resources to go up against a country... Putin has the power of Russia behind him, while Trump is just a businessman. Trump cannot use the power of the White house to wage war against Russia for personal business.