The Trump Organization has very likely been money laundering the financial proceeds from Russian organized crime for years.
As a result, Trump doesn’t want or cannot do three things. First, Trump doesn’t want the FBI or special counsel Robert Mueller to look at his company’s or his financial records. Second, Trump can’t say anything bad about the Russian government, oligarchs, or Putin. Third, Trump cannot clearly say that Russia used online misinformation and other methods to manipulate public opinion during the 2016 election.
Russian Interference in our election has never been about changing votes on voting machines. The Russian strategy has sought to affect the political opinions of gullible American people. In particular, the Russian strategy targeted people who did not pay very close attention to politics or the election, but who could and did vote.
Money laundering is the thing “they” — Russian oligarchs, Putin and numerous Russian business entities — “have on” Trump.