NEW YORK (FOX5NY.COM) - Nearly two years ago, Donald Trump raised his right hand and solemnly swore to "faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States."
Every president has started his time in office with that oath of office, prescribed in Article II of the United States Constitution.
But while nearly every president has been accused of violating that oath, the frequency and range of accusations against President Trump inspired Corey Brettschneider, a constitutional law professor at Fordham Law and Brown University, to write The Oath and the Office: A Guide to the Constitution for Future Presidents.
President Trump's boundary-pushing began virtually as soon as he entered office with his refusal to divest from his businesses, triggering lawsuits alleging his violation of the Emoluments Clause, followed by his ordering the Travel Ban, which the Supreme Court upheld a year and a half and several versions later.
Among the additional alleged violations since then have been his last week's revocation of CNN reporter Jim Acosta's press pass and appointment of Matt Whitaker as acting attorney general overseeing Special Counsel Robert Mueller's Russia investigation.
But in his book, Brettschneider finds cautionary tales throughout American history, up to and including President Obama's use of drone strikes and the Bush administration's authorization of torture in the so-called war on terror.
"The challenge in writing a book is to not write about one president, it's to write about all of them," Brettschneider said. "To be honest about the fact that both Democrat and Republican presidents have violated the constitution, and to call them out."
Future presidents can avoid these problems by looking to what our first president said before he took the oath for his second term in office, he said.
"Even George Washington who was motivated to honor the Constitution recognized that, 'I might fail and if I do fail, subject me to criticism, subject me to constitutional punishment,'" Brettschneider said.
The courts are one place to keep a president in check. Congressional oversight or impeachment is another. But Brettschneider said that ultimately it is up to we, the people.
"I want people to demand that their candidates speak to their willingness and understanding of the constitution and their willingness to defend it," Brettschneider said.
The Oath and the Office: A Guide to the Constitution for Future Presidents (W.W. Norton & Co.) by Corey Brettschneider | books.wwnorton.com