The Congress isn't a winner take all institution. There are substantive protections for minority opinions. Many votes require a 3/5 or 2/3rds majority.
BTW: The parties aren't in the Constitution.
The US Founders had the notion that elected officials would represent the people and not represent a party. The US Founders would loath the fact that mid term elections seem to be about which faction controls the Congress.
The stupid parties really hurt this nation.
What is really amazing is that the partisan divide is getting deeper when the positions of the parties aren't that far apart.
Trump has a long history of jumping between parties. His positions on most issues are closer to the traditional Democratic views than the traditional Republican view.