“The difference is really with volume, not in kind,” said Kevin Evans, a Florida International University professor who has researched the practice of presidential signing statements. “Senator Obama had a very different view than President Obama.”

The latest — and potentially hottest — flash point involves Obama’s decision over the weekend to trade the release of Army Sgt. Bowe Bergdahl, the sole remaining U.S. military prisoner of war, for that of five Taliban commanders who were being held at the detention center at Guantanamo Bay, Cuba…

As president, Obama has issued close to 30 signing statements; in the 2013 Defense Authorization Act alone, he challenged more than 20 sections of the law. Among the challenges have been assertions of his power to close Guantanamo Bay, for instance, and to disregard whistleblower protections.