Pete, you seem to be mixing up politics and evidence. Just who is popular with Trump fans and/or enablers, and who is not, does not seem to have any nexus, as to who is more creditable as to the current lay of the land as to the gravitas of Trump's so far undocumented allegations. And Trump has a track record of never letting accuracy get in the way of generating buzz, so that he dominates the news cycle, particularly if there is another cycle in play (like the Sessions fiasco), that he wants to get off the front page.
Also any investigation of Trump would need a sign off from FBI Director James Comey, who voted Romney in 2012 and is a registered Republican. If there was in fact an investigation of Trump it came with Comey authorising the wiretap request before a federal judge. Given Comey; a role in 2016 he wouldn't have ever made that judgment unless he could justify it before Congress.
In short: either there's a smoking gun and Comey knows it in which case Trump is in trouble or there's nothing as Tom Cotton acknowledges.