Earlier this month, during one of his new across-the-aisle good-will tours, President Obama pleaded with Senate Republicans to ease up on their record number of filibusters of his nominees. He might as well have been talking to one of the statues in the Capitol. Republicans have made it clear that erecting hurdles for Mr. Obama is, if anything, their overriding legislative goal.

There is no historical precedent for the number of cabinet-level nominees that Republicans have blocked or delayed in the Obama administration. Chuck Hagel became the first defense secretary nominee ever filibustered. John Brennan, the C.I.A. director, was the subject of an epic filibuster by Senator Rand Paul. Kathleen Sebelius and John Bryson, the secretaries of health and human services and commerce, were subjected to 60-vote confirmation margins instead of simple majorities. Susan Rice surely would have been filibustered and thus was not nominated to be secretary of state.

Jacob Lew, the Treasury secretary, was barraged with 444 written questions, mostly from Republicans, more than the previous seven nominees for that position combined. Many were ridiculous and had nothing to do with Mr. Lew’s fitness for office, such as a demand to explain the Treasury’s social media policies, or questioning an infographic on the department’s blog eight months ago.

Gina McCarthy, the nominee to lead the Environmental Protection Agency, is being blocked by Senator Roy Blunt of Missouri until he gets the answers he wants on a local levee project. And Thomas Perez, nominated to be labor secretary, is being held up by Senator David Vitter of Louisiana, who is angry about the Justice Department’s enforcement of voting rights laws. By comparison, there were four filibusters of cabinet-level positions during George W. Bush’s two terms, and one under President Ronald Reagan.