List four challenges faced by the new government within the US

Challenge 1: A new Democratic-held House : The new US House of Representatives will now be a constant thorn in the President's side.  When the Democrats won control of it in November's midterms their greatest prize was probably the power of the subpoena.  Led by veteran insider Nancy Pelosi, they can now compel witnesses to cooperate with the many investigations they're currently setting up.  The aim?  To put the first-term President under constant pressure.

Challenge 2: Legislative gridlock : In that environment, will any serious bipartisan legislation see the light of day?  Probably not.  Donald Trump may market himself as a dealmaker but if the shutdown is any guide, reserves of goodwill are low on both sides.

Challenge 3: The Mueller inquiry: Of course, several previous presidents have survived, and yes thrived, politically, despite clashes with Congress.  The biggest unknown hanging over Donald Trump (and friends) is the Russia investigation.

Challenge 4: The threat of impeachment : With the Russia probe coming towards a conclusion, impeachment is a topic that's moved from the margins slightly closer to the mainstream.  "If Bob Mueller comes to the American people … with concrete evidence that the President committed crimes then it is the duty of the Congress to impeach him and try him," Ms Solis Doyle said.  A few newly elected Democrats have caused controversy by demanding Mr Trump be impeached soon.  Rashida Tlaib, the first Palestinian-American elected to Congress, notably used impolite language to express her views, outraging some right-wing cable news hosts as a result.

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