Rob Portman isn’t a bomb thrower. But his pitch last week for an amendment cracking down on countries that artificially weaken their currencies threatened to blow up President Barack Obama’s trade agenda, and exposed a deep split in approaches among Republicans who face the voters in 2016.
A trio of Rust Belt Senate Republicans — Ohio’s Portman, Ron Johnson of Wisconsin and Patrick J. Toomey of Pennsylvania — ended up voting for Trade Promotion Authority, backing Obama, Republican leadership and a top priority of the U.S. Chamber of Commerce.