Biggest down- and upgrades in presidential history

[President Johnson]

Analogue to the senate and gubernatorial threads on that matter.

I'd say biggest upgrade was Buchanan -> Lincoln (though Trump -> Biden is a modern day contender)

Biggest downgrade: Obama -> Trump

[Vosem]

Buchanan --> Lincoln is probably the biggest upgrade ever, but others in a similar category might include Adams --> Jefferson, Wilson --> Harding (saying much more about Wilson here), and Carter --> Reagan.

Biggest downgrades are actually a bit tougher. Underrated one might be Taylor --> Fillmore; I guess on the theory of normal Presidents leading to disasters you could include Taft --> Wilson and Ford --> Carter here.

Biggest downgrade: Obama -> Trump

Bush/Obama/Trump/Biden has actually been a remarkably bad run. I don't think we've had a President who wasn't an enormous disaster, by their own standards if evaluated honestly, since Bill Clinton.

[bagelman]

Lincoln -> A. Johnson

[darklordoftech]

Upgrades:
- Polk - Taylor
- Buchanan - Lincoln
- A. Johnson - Grant
- McKinley - Roosevelt
- Hoover - Roosevelt
- Nixon - Ford
- Bush 43 - Obama
- Trump - Biden

Downgrades:
- Quincy Adams - Jackson
- WH Harrison - Tyler
- Taylor - Fillmore
- Lincoln - A. Johnson
- L. Johnson - Nixon
- Clinton - Bush 43
- Obama - Trump

[OSR stands with Israel]

Upgrade : Buchanan to Lincoln
Downgrade: Lincoln to Johnson

[TheTide]

Reagan to Bush 41 was a fair upgrade.

[HisGrace]

Upgrade- Hard to beat Carter to Reagan. Morning in America as they said. Adams to Jefferson, Johnson to Grant, and Harding to Coolidge would be HM's.

Downgrade- Prob Monroe to JQA

[Tartarus Sauce]

Upgrade : Buchanan to Lincoln
Downgrade: Lincoln to Johnson

The objectively correct answer.