There certainly is a lot of political pressure for states to adopt the new federal tax codes. But there is no law that requires them to do so.

S. equestrian team at the 1924 Summer Olympics
Jack Barry (baseball) (1887–1961) given name John American baseball shortstop and coach
John Patrick Barry (1893–1946) Canadian politician and lawyer
John Vincent Barry (1903–1969) former Supreme Court justice for Victoria Australia
John Barry (WD-40) (1924–2009) American business executive; popularized the WD-40 water-displacing spray and lubricant
John Barry (composer) (1933–2011) British film composer
John Barry (set designer) (1935–1979) British film production designer
Living people
John Barry (tennis) (born 1928) New Zealand tennis player
John M. Public.