Now that AG Bill Barr has covered for him so that Mr. Trump's 'exoneration spin' can swing into full force and he's threatening revenge against all his critics, it occurs to me that this particular phase of retaliation by Donald Trump may be a telling part of the Regulus caution he lives under.
For as you know, royal Regulus rises in Trump's natal chart (assuming its 10:54 am timing is accurate with ASC 29Leo55) so the 'kingmaker' star's caution is especially critical for Mr. Trump: 'success if revenge is avoided; if not, all that has been gained will be taken away'.
So if you wish, see a previous post Will Regulus Assure the Destiny of Donald Trump? for more details and a link to Trump's natal horoscope. Plus, for an extra 'punch' of revenge and grudge-holding in his character, it's interesting that Trump's natal Tisiphone, asteroid of retaliation, is positioned @22Sag24 which opposes his natal Sun (22Gem55) and thus conjoins his natal Moon (21Sag12) - on his (fated, karmic) Nodal Axis! Now with Regulus at Ascendant, Tisiphone on Nodal Axis with Sun and Moon - the man embodies retaliation and revenge. And that is one of, if not his primary, Achilles Heels (which is not so say that he hasn't others).
Therefore, it seems possible to me that the Great Saturn-Pluto Conjunction @22Cap46 (January 12, 2020) conjunct Trump's natal Vertex of fated encounters will bring him his just desserts after all due to the many ongoing investigations now being pursued around the country, NY in particular (thanks to Mr. Mueller's 'farming them out').
Guess we'll have to see how Trump and America fares as 2019 closes, won't we? And as always, America is my only nag in the race!