What are the chances that Trump is using blackmail on fellow Republicans?

Sarah Kendzior postulated a few days ago that, while careerism and opportunism certainly enter into the equation of why and how former Republican adversaries of Trump have become fawning sycophants (my term, not hers), you cannot discount that blackmail and threats of blackmail might be involved, particularly given Trumps history, possible collusion and the extent of Russian hacking into the RNC computers and those of individuals.
Putting aside (or trying your best to) your personal feelings about Trump, how good are the odds that blackmail is playing at least a part of what we see happening in government circles these days?