Lawmakers in blue states like California may prefer to tax the rich, but there’s always a risk: What if the rich just move elsewhere?

Last week Assemblymember Alex Lee said he was introducing a new tax on “extreme wealth.” It wasn’t the first time the Milpitas Democrat pushed the idea. But this year, he had back up. 

Lawmakers from seven other states, including Connecticut, Hawaii, New York, Illinois and Washington were introducing new taxes for the rich on the same day. 

“The counter argument is that the rich will just leave,” said Lee. “Well, this is kind of the strategy of ‘You can run but you can’t hide.’”

Lee’s proposal would apply to individuals with a net worth of $50 million or more, taxing their wealth at 1% annually. Wealth beyond $1 billion would be taxed at 1.5%. The tax would apply to about 23,000 households, or the wealthiest 0.1% in the state, and would raise about $21.6 billion in revenue per year, according to calculations from UC Berkeley economist Emmanuel Saez, who helped design Massachusetts Sen. Elizabeth Warren’s national wealth tax proposal and had a hand in some of the state-level proposals.

Unlike income tax, a tax on overall wealth is unprecedented in the U.S. The proposal would apply to assets including shares of privately owned companies, art and collectables, “financial assets held offshore” and…