During which years in US history has any party had 2/3 majority in the Senate?

If the precedent has now been set that impeachment is merely a “political process”, then future presidents are essentially free to commit crimes at will as long as they continue making decisions that favor their base. 2/3 majority seems impossible to achieve in the future, so was just curious as to how common it ever was.

In theory, senators still have to worry about re-election, even if they aren’t at risk of becoming a super-minority.

But your concern of a democracy that is essentially broken is valid. I think an even bigger problem that the constitution has is that it requires 38 states to be amended, and these days, that means it can be amended for measures that are merely popular but not necessarily helpful (e.g. we’re much more likely to pass laws that protect the American flag from a lit match than we are passing laws that actually protect democracy, like campaign finance reform).

I agree. I feel Senators will place their own self-interest ahead of loyalty to a President from their own party. If Senators end up losing elections because they protected a President who should have been removed, they won’t do it.

86% of the US senate was Republican at the end of 1869.

OP: By my rough math, Party Divisions of US Congress shows 2/3+ Senate majorities in:

1789-91 (pro-administration)
1795-1801 (Federalists)
1803-25 (Democratic-Republicans)
1837-39 (Democrats)
1861-75 (Republicans)
1907-09 (Republicans)
1935-43 (Democrats)
1963-67 (Democrats)