Pakistan, July 20 -- Donald Trump has spent six months testing the limits of his authority like no other modern US president, say analysts - browbeating Congress and the courts in a power grab that may come to define his second term.

Since January, the Republican leader has repeatedly pushed to secure more power for himself, calling for judges to be axed, firing independent watchdogs and sidestepping the legislative process.

Barbara Perry, a University of Virginia professor and an expert on the presidency, called Trump's successes in shattering the restraints on his office "frightening."

"All presidents have been subject to Congress's and the Supreme Court's checks on their power, as well as splits in their own political parties," she ...