July 17 (Bloomberg) — Washington is buzzing this summer about inversions, and the chatter has nothing to do with the weather.

This week, Treasury Secretary Jacob J. Lew and Senate Majority Leader Harry Reid became the latest to press for a crackdown against corporate inversions. These are when U.S. companies switch their addresses to low-tax nations like Ireland, often through a takeover of a smaller company, reducing their tax bills while typically keeping their headquarters and listings in the U.S.

Democratic lawmakers were coalescing yesterday around their resistance to these deals as a possible election-year rallying point. Reid, of Nevada, called for comprehensive rules against such changes of address. A handful of bills working through Congress already include language aimed at cracking down on the practice. White House Press Secretary Josh Earnest said President Barack Obama will discuss the issue more in coming weeks.