GOP governors pledge to sue over Biden's business vaccine mandate

President Biden responded Friday to a pledge by some Republicans to sue over an incoming rule issued by the Labor Department requiring businesses with more than 100 employees to require that workers be vaccinated or undergo weekly testing. 

Republican governors are slamming the president over the yet-to-be-developed rule, declaring it an overreach and unconstitutional. It's the most sweeping vaccine mandate the federal government has yet announced.  "Have at it," the president retorted during a school visit Friday morning when a reporter asked if the new requirements constitute overreach and could be confronted with legal challenges.