So what's the holdup on impeachment? The account of the conversation has been released, as has the "whistle blower's" report (that was apparently written by DNC lawyers with the assistance of Shiff's people). The news media is pounding the propaganda that there's an appropriate reason for impeachment, yet only a bare plurality favor it. So Pelosi is being circumspect on the matter (with good reason). Trump's (strong) support among his base has gone up since this "inquiry" began. And I suspect he feels he can pick up independent support as he uses his bully pulpit to show how this entire "Ukraine-gate" matter is simply another manufactured charge (like "Russian collusion") by the democrats and their comrades within the deep state bureaucracy.
Of course Trump sought Ukrainian help with taking out Joe Biden as the frontrunner, just as Hillary did so with the Russians in 2016 against Trump. It is a distinction without a difference that Trump did so directly (and appropriately), as the top law enforcement officer of the USA, while Clinton was forced to do so through "private" contractors. They are two sides of the same dirty coin.
Trump is no dummy - Biden was definitely his most dangerous rival, as the (ostensible) "capitalist" leading dem candidate. Trump knew that by knee capping Biden, Warren (most likely) would end up the nominee. And her naked Marxism (not to mention her penchant for stupid inaccurate claims about her background) will almost assuredly render her unelectable to a great number of independents. He may be an odious boor (yes "boor" not "bore"), but he sure does know how to play to win.