Never happened before!

Thank goodness for ignorant supporters.    Of course, it may not just be the supporters.

Does the name Merrick Garland ring any bells?

Let's check with Snopes, shall we?

Over the past several decades — most historians date the trend beginning in 1987, when the Democratically-controlled Senate rejected Ronald Reagan’s nomination of conservative U.S. Circuit Court judge Robert Bork — the appointment of Supreme Court justices has become increasingly politicized, with both the executive and legislative branches attempting to subject nominees to ideological litmus tests over and above their professional qualifications.

In March 2016, following the death of Associate Justice Antonin Scalia, a Reagan appointee and one of the more conservative voices on the court, President Obama nominated federal appellate judge Merrick Garland, who was described as “centrist” by the mainstream media and “left-leaning” by those on the right, to fill the vacancy. He did this despite the fact that Senate Majority Leader Mitch McConnell of Kentucky had already announced — on the day Scalia died — that the Republican-controlled Senate had no intention of confirming any nominee chosen by Obama.

[...]

Obama’s nomination of Merrick Garland expired when the 114th Congress ended its session on 3 January 2017. It was the longest period of time a Supreme Court appointment remained before the Senate in U.S. history.

Eleven days after President Trump’s inauguration on 20 January 2017, he nominated U.S. Circuit Court of Appeals judge Neil Gorsuch to fill Scalia’s vacancy. Democratic Senators vowed a fight, insisting for starters on keeping the rule that a majority of 60 votes be required for confirmation (which would mean that at least eight Democrats would have to vote “yea”), and threatening a filibuster.

  Snopes

And that's just the most famous/recent incident of blocking a nominee.   "Obstructionists."  Let's talk about "obstructionists".  How's that obstruction of justice investigation coming along?

...but hey, do what you want...you will anyway.