The relationship began with Russian oligarchs laundering rubles into dollars by investing in Trump properties. This, at a time when Trump was having problems getting American or any other country’s banks to finance his dealings due to his multiple failed ventures , lawsuits, and bankruptcies.
When Trump ran for President as a lark and then gained traction Putin saw a chance to help defeat Hillary. When Hillary made the claim in 2011 that the Russian elections were rigged to favor Putin , it ( justifiably, IMHO) led to massive protests and unrest within Russia. In Putin’s mind, the US interfered with our elections first and he is justified in retaliating.
Putin continues to control Trump through money. The Trump ( IMHO ) empire is a house of cards, ready to tumble at any moment. Without continued inflow of new investment monies to finance the empire , it will crumble. Which also explains why we will never ever see his tax returns.
Further, the Russians want Exxon to develop oil fields in the frigid waters north of Russia. Russia itself does not have the expertise to tap this resource. Obama had imposed sanctions which prevented Exxon from doing that. Trump is much more pliable. He installed the Exxon CEO ( who was not even seeking a government position of any kind and did not previously know Trump) as Secretary of State. Trump has already or is in the process of releasing the sanctions . So, the oil deal moves forward, and Trump Corporation maintains the sorely needed flow of investment capital.
Trump is not the only one who has figured out that the rise of the oligarch class in Russia has created a pool of money controlled by a very few individuals with little or no government oversight of those funds. Flynn, Manafort, Carter Page, Wilbur Ross, Trump, and many others we have not yet heard of saw an opportunity for personal enrichment and leaped on it.
Wilbur Ross, now Secretary of Commerce, has not received much press ( yet) but he seems to be involved in money laundering billions of rubles into dollars through his position as vice-chairman of the Bank of Cyprus.
The GOP is caught in a dilemma. They , through a bizarre character named Donald Trump, gained the most power they have had in Washington in over 100 years. They are ever so close to being able to steamroll their entire agenda into law, yet they are dealing with an unpredictable , narcissistic , mentally unstable President. Any attempts to fire or replace Trump will completely derail the agenda. So, they are frozen in place, watching the circus, trying to move forward with their agenda, and compromising their loyalty to the country in the process. They keep hoping he will turn out to be a savvy chess player who is manipulating everything in grand fashion.
Brexit was a backlash from people whose incomes and job prospects are declining , mistakenly directed at immigrants. Trump represented a similar phenomena. ( In fact, the real problem is one of class warfare, with the people at the top accumulating ever greater percentages of the world’s wealth). France saw what happened in the US and UK and learned from it. After initially supporting a Trump like candidate they made a hard turn to the center with Macron. South Korea threw out the right wing leader for one from left of center.