See, 13 states can drop out of earlier associations and form their own country, but if 11 try the same thing, it's a no-no.
(Hideously uncomfortable historical note: somebody's gonna wonder if slavery might be a limiting factor, too. The short, sad answer is no; it was legal in all 13 colonies at the time of Revolution and only Vermont and Massachusetts had put an end to the practice before the 18th Century ended. What's the Oscar Wilde quote about "We're all standing in the gutter but some of us are looking at the stars?" Gotta do more than just watch, sir).
CHICAGO RAILROAD FAIR, 1948
50 minutes ago