One reason is that second quarter earnings have been better than expected.
Another reason is the inflow of cash from increasing global profits.
Yet another reason is that the market believes the worst case is that Trump is impeached and resigns. So what? That turns Vice President Pence into President2B Pence, who has the same agenda as President Trump. He is the experienced Washington insider who can ride into the White House on a white horse with the political capital to actually accomplish something.
The most significant difference between the Trump Agenda and the Pence Agenda is the latter contains socially conservative goals, which have a low probability of passage. If he advances those social goals first, like Trump advanced healthcare reform first, his agenda will likely become stalled as well.
But, what happens to the Trump/Pence Agenda when President Pence takes over, if either the House or the Senate is then controlled by the opposition party? Their agenda remains in greater peril than Wall Street seems to recognize.