For the purposes of this question, a "senior moment" includes, but is not limited to:

• Falling to the ground or seeming unable to walk (absent specific medical explanation)

• Trying to shake hands with someone who isn't there

• Freezing while speaking for >=0.33 McConnells (1 McConnell = 30 seconds) for no apparent reason

• Reading words in a speech that are clearly meant to be instructions (eg "repeat the line again", "pause for applause")

• Appearing genuinely confused about the time, place or year

• Claiming that he recently met people who are long dead

• Confusing the names of people who he should know well

• Confusing the names of countries or states

Obviously there is a lot of discretion in this question, and as such I will not bet in the market. I will base resolutions both on my own judgement and how it is reported in the press.

One important point I will bear in mind is that anybody can misspeak (eg Bush condemning "the illegal invasion of Iraq" when he clearly meant Ukraine) but that in the case of misspeaking the speaker usually realises their error and rapidly corrects it. Misstatements which are rapidly corrected will not results in a YES resolution.

If the incident is reported but not publicly visible (eg "Biden Shocks Generals By Confusing Russia and Romania In Situation Room") I will apply a high standard of proof and only resolve YES if it is reliably reported to have occured in independent/friendly news sources (eg Fox News+Breitbart is not sufficient, Fox News + NY Times probably is).