I think Mitch is playing us for fools,again,

[HariSeldon]

7. I dunno

This delay may give Democrats the Senate majority during the impeachment trial, which gives them control of the trial procedure. A Senate impeachment trial has special legal powers...powers that were denied to the House managers by a craven majority of Republican Senators. Powers to pierce Presidential privilege and classification of records, and compel witnesses to testify under oath.

By delaying, McConnell may actually be handing these powers to the House managers.