Saez who...

   has to check their prior beliefs at the door? Not Emmanuel, nor his co-authors Henrik Kleven, Camille Landais, and Esben Schultz;

 High top-tax rates may induce top earners to migrate to countries where the tax burden is lower, thereby limiting the redistributive power of governments and potentially creating harmful tax competition. 

Gee, might there be some who'd dispute that the power to confiscate other people's income doesn't corrupt (sometimes absolutely)? But being blithely obtuse is bliss, as the economists double down in their conclusion;

...these schemes impose negative fiscal externalities on other countries by reducing their capacity to collect taxes from top earners. .... Absent international tax coordination, preferential tax schemes to high-income foreigners could substantially weaken tax progressivity at the top of the distribution. This will require international policy coordination and the design of rules regulating such special schemes in the EU in coming years. 

 In other words, these four economists favor monopoly! However, where is the evidence that 'tax progressivity' is a good thing? After all, the wisdom of the ages is that coveting that which is thy neighbor's is unhealthy. Especially when these four admit that at a rate of 35% a country will probably maximize its revenue (only a good thing if you're receiving it; a position in which only a minority can be).

C'mon guys, an unexamined life isn't worth living.