Trump's Blowout Loss - 11-8-16, Is GOP Relevant?

It might depend on size of Trump's loss to Hillary.

If Trump loses popular vote to Clinton by 15-20%, the GOP will be marginalized for a long time!

Trump will cease to be a "principal" in the GOP party (as if he ever was) and the "infighting" will begin in earnest.

Tne GOP's damage control won't be able to prevent the Trumpification of a good # of GOP office holders who'll be flushed down the drain in the wake of a substantial Democratic Trump-backlash.  The Democrats have the edge when it comes to voter turnout in November (Clinton's voter turnout efforts) and will capture many states that are nominally red/swing-state.  

Trump's "base" supporters will fall away from the GOP as a party and what remains of that political entity will be maintained by a threadbare contingent of party loyalists keeping the apparatus on life-support.  It'll revert to being a regional (Southern-based) party with greatly diminished prospects of returning to a truly national presence.

The Democrats will have the White House, the U.S. Senate and be roughly equal to the GOP in the House of Representatives.  If The election becomes a full-blown landslide the House will revert back to Democratic control with Madam Speaker Nancy Pelosi again assuming the gavel.

Under this scenario the Democrats will engage in a 100-day sprint to churn out as much legislation as possible along with confirming moderate U.S. Ct. of Appeals Judge Merrick Garland as Supreme Court Justice to replace the late Antonin Scalia.  The Court becomes a 5-4 "moderate" majority & a bullwark against right-wing "roll-back" case law.  Of course, Republicans will be sputtering, fuming + foaming at the mouth at their new-found precarious position of poliltical disadvantage.