Energy and Trump's diesel deal with Putin will become major issues if Democrats gain control of Congress. Axios. President Trump's energy policy and investment deals could become prime targets for Democratic investigations if the party wins control of either house of Congress. Trump's relationship with Moscow will once again be in the spotlight. Democrats in both chambers are expected to investigate Trump's diesel deal with Moscow, arguing it violates a 2022 law banning Russian fuel imports. They could also affect US banks and ports, which lawmakers have warned could face congressional investigations.