When the president violates the Constitution, there has to be a remedy short of impeachment, which is a blunt political tool that does nothing to reverse the illegal actions at issue. Speaker Boehner’s proposed lawsuit seems measured to challenge what is perhaps President Obama’s most egregious extra-constitutional action, rewriting the Affordable Care Act to suit his political needs.
When Congress passes a law, it is the president’s duty to enforce it. The president has discretion in how to enforce it, to be sure, but he can’t suspend, waive, ignore, or change it. The House of Representatives is thus well-placed to sue over the institutional injury that the executive branch has foisted on the legislative branch.