The Tweet you referenced is not currently a violation of the Twitter Rules.

A Twitter spokesperson said regarding a misleading video clip that appears to show Democratic presidential candidate Joe Biden endorsing the U.S. as a European nation. Twitter is currently drafting new privacy policies around misleading or altered videos but it is unclear if it would result in removal of the clip. Misinformation concerns are growing in anticipation of the 2020Census and thenthe election, and many social media platforms arechanging their policies to expose these falsities. (The Hill — January 3, 2020).