After refusing to even interview or hold hearings on President Obama’s nominee to replace deceased Justice Antonin Scalia (appointed 1986 by President Reagan) on the Supreme court, Speaker of the House, Paul Ryan is demanding that, because of President trump's "mandate," Democrats should bow to the will of the people and quickly approve President Trump’s nominee who has not yet been announced.
Looking back a few weeks
On leaving office President Obama had an approval rating of between 57% (very conservative anti-Obama Fox News) and 62% Rasmussen (independent) and won his re-election with 332 Electoral college and 51.1% of the popular vote.
By comparison, President Trump now has a disapproval rating of about 53%, having plunged more than 5% between January 25 and January 27 (based on a Gallup Tracking Poll), and President Trump lost the popular vote by about 3 million, a number he keeps trying to explain by claiming millions of illegals voting for Secretary Clinton.
Republican actions in the past
But the important point to remember is that with months to go in his term President Obama nominated a mainstream judge, Merrick Garland, to replace conservative Antonin Scalia, who died in February, 2016, and Republicans in the Senate announced that they would not permit a vote on Judge Garland or even meet with him on an official basis.
The same people are now complaining that the Democrats are automatically disapproving of any Trump nominee to fill the same vacancy, calling them obstructionists.
President Obama succeeded in placing two judges on the Supreme Court, Judge Sonia Sotomayor to fill the vacancy created by the retirement of Justice David H. Souter and Solicitor General Elena Kagan to replace retired Justice John Paul Stevens.
The Republican Senate is now “shocked, shocked to find” (Movie Casablanca, 1942) that, after they had blocked virtually every Obama proposal beginning with their announcement on day one of the Obama Presidency that their primary goal was to make Obama a one term President, Democrats are now trying to block action by President Trump who has far lower ratings (and far less support, let alone a mandate.)
John Boehner, who was Speaker of the House, said the following about Obama's plans, “We're going to do everything — and I mean everything we can do — to kill it, stop it, slow it down, whatever we can.”
Democratic reaction
Although they don't have a majority and can't defeat nominees, in the long run, Senate Democrats have used the Senate Rules to block nominees by refusing to appear for the committees' votes on nominees.
Republicans are the majority in every comittee now and can easily vote for any nominee despite Democratic objections but the Senate rules also require that at least one member of the other party be present for the vote.
If this action holds, the only recourse for President Trump is to wait for Congress to recess and then make a recess appointment which doesn't require the Senate "advise and consent" to that person. That; however, would place restrictions on the appointee, including the automatic termination of their appointment at the end of the current Senate session.