The smoking gun: Don Trump Jr brags about the money that's been pouring in from Russia.

[calimary]

24. Uh YEAH.

From Josh Marshall at Talking Points Memo (bold emphasis is mine):

Let's start with the basic facts. There is a lot of Russian money flowing into Trump's coffers and he is conspicuously solicitous of Russian foreign policy priorities.

I'll list off some facts.

1. All the other discussions of Trump's finances aside, his debt load has grown dramatically over the last year, from $350 million to $630 million. This is in just one year while his liquid assets have also decreased. Trump has been blackballed by all major US banks.

2. Post-bankruptcy Trump has been highly reliant on money from Russia, most of which has over the years become increasingly concentrated among oligarchs and sub-garchs close to Vladimir Putin. Here's a good overview from The Washington Post, with one morsel for illustration ...
Since the 1980s, Trump and his family members have made numerous trips to Moscow in search of business opportunities, and they have relied on Russian investors to buy their properties around the world.
“Russians make up a pretty disproportionate cross-section of a lot of our assets,” Trump’s son, Donald Jr., told a real estate conference in 2008, according to an account posted on the website of eTurboNews, a trade publication. “We see a lot of money pouring in from Russia.”


http://talkingpointsmemo.com/edblog/trump-putin-yes-it-s-really-a-thing