Mayor Bloomberg voiced a warning recently. He cautioned New Yorkers about forever raising taxes on the rich. Whether you like it or not, he said, the rich are mobile.

And when they move, they hurt the government that has badgered them with the higher taxes.

This is true in France. The new socialist leader there wants to raise taxes a lot on the biggest earners. And those big earners are lining up to flee to Switzerland and Belgium and other countries.

This is predictable because the rich have done this for centuries. All over the world. Movin’ on out is one of the privileges rich people enjoy. They don’t have to grin it and bear it. They don’t have to worry if they can sell their house or find new work.

Britain made a sport out of gouging the rich in the 1960’s and 70’s. By the time Margaret Thatcher arrived on the scene the UK was starved of investment. The rich refused to invest in much in the UK because the taxes on their returns were insulting. So they shipped untold billions out of the country and invested it elsewhere.

And big earners simply moved out. To avoid the income taxes on their big earnings. For instance, virtually all of Britain’s major authors fled to Europe. Because Britain was sucking up so much of their royalties.