Gavin Newsom urges a national 'billionaires' tax' while fighting one in California
(www.theguardian.com)
Can also be in the sense that if you enact it in California then they can pick up and leave for Texas or Florida and still mess up the country’s politics but leave California without the ability to get any taxes from them. Whereas if you enact it nationwide then they’d have to skip the country entirely to dodge it which would be more difficult and not advantage states that don’t agree.