On June 25, 1992, (then) Chairman of the Senate Judiciary Committee, Sen. Joe Biden (D-DE), delivered an emphatic floor speech, stating:

…it is my view that if a Supreme Court justice resigns tomorrow or within the next several weeks, or resigns at the end of the summer, President Bush should consider following the practice of a majority of his predecessors and not — and not — name a nominee until after the November election is completed.

And…

The Senate, too, Mr. President must consider how it would respond to a Supreme Court vacancy that would occur in the full throes of an election year. It is my view that if the President goes the way of Presidents [Millard] Fillmore and [Andrew] Johnson, and presses an election year nomination, the Senate Judiciary Committee should seriously consider not scheduling confirmation hearings on the nomination until after the political campaign season is over.

Source: Joe Biden, 1992: No Supreme Court Pick Until After Election (breitbart.com)