I wonder if Democrats remember the old saying, "What goes around comes around." Merriam-Webster defines the meaning as, "Used to say that if someone treats other people badly he or she will eventually be treated badly by someone else."
In 2013, Senate Majority Leader Harry Reid pushed through a controversial change to Senate rules that made it easier to push through Obama's nominees. The change basically eliminated the practice of the minority party filibustering to prevent the Senate confirmation of a presidential appointee. After the rule change, it only took 51 votes to confirm an appointee, not the 60 votes that had been required to end a filibuster. His rule change did still allow filibustering Supreme Court nominees, but it opened the door for more change.
In 2017, Senate Majority Leader Mitch McConnell pushed through a similar rule, by a 52-48 vote along party lines, to end filibustering Supreme Court nominees. It led to the 55-45 confirmation of Neil Gorsuch and the 50-48 confirmation of Brett Kavanaugh as Supreme Court justices. (Few things terrify a Democrat as much as a Supreme Court composed of a majority of justices who believe the Constitution and its amendments still means what it did to those who approved it.) This certainly seems to be an example of "What goes around comes around."
I wonder what will happen the next time we have a Democratic president and a Republican-controlled House? Even if Republicans don't control the Senate, will they spend months between nomination and confirmation digging up 35-year-old, unsubstantiated, trash on a Supreme Court nominee, trying to destroy his/her reputation, as they did with Justice Kavanaugh? Will a majority Republican House spend years trying to dig up some "crime" by the president, in an effort to impeach him/her?
Can you imagine the frenzy if Democrats and the mainstream media caught President Trump, on an open mic, telling the Russian president, "This is my last election. After my election I have more flexibility." President Obama made the comment. It would be humorous to see the results of a poll suggesting the comment had been made by Trump and asking if it was an "impeachable offense."