Probably an easy quick question for those in the know but I’m too lazy to look it up.
When was the last time one party (Dem or Rep) controlled the house, senate, and presidency?
Right now.
In case the OP was looking for the last time before right now, the Democrats controlled all three from 1993-1995. The Republicans retained control of Congress for the last six years of the Clinton administration and will lose it when the new Congress meets next year.
Before the Bush administration? 1993-94. Clinton was President, the Democrats had a majority of 7 in the Senate, and 41 in the House.
And before that, I guess it would have to be Carter, but I don’t remember if the Democrats held the Senate during his term. I know 1994 famously ended 40 years of Democratic control of the House, so only during the Carter, Johnson, and Kennedy administrations could this possibly have been true.
The Senate was Democratic under Carter; it switched to Republican when Reagan was elected.