FILE - In this Sept. 1, 2021, file photo Joint Chiefs of Staff Gen. Mark Milley speaks during a briefing at the Pentagon in Washington about the end of the war in Afghanistan. Milley is expected to testify with Defense Secretary Lloyd Austin at a Senate hearing on Tuesday, Sept. 28, and a House panel on Wednesday, Sept. 29.  The hearings originally were meant to focus on the Afghanistan withdrawal and the chaotic evacuation from Kabul airport last month. (AP Photo/Susan Walsh, File)

WASHINGTON (AP) — Gen. Mark Milley has been the target of more political intrigue and debate in two years as chairman of the Joint Chiefs of Staff than any of his recent predecessors were in four.

One after another, firestorms have ignited around him — unusual for an officer who by law is a whisperer to presidents and by custom is careful to stay above the fray.

From racial injustice and domestic extremism to nuclear weapons and the fitness of Donald Trump as commander in chief, Milley has become entangled in politically charged issues, regularly thrusting him into the news headlines.

Milley is expected to face tough questioning on those and other issues when he testifies with Defense Secretary Lloyd Austin at a Senate hearing today and a House panel Wednesday. The hearings originally were meant to focus on the Afghanistan withdrawal and the chaotic evacuation from Kabul airport last month.

But since then, Milley has come under fire from Republicans for his portrayal in a new book as having taken unusual — some say illegal — steps to guard against Trump potentially starting a war with China or Iran or ordering an unprovoked nuclear attack in the final months of his presidency. Milley was reported to have agreed with House Speaker Nancy Pelosi’s assertion in a January phone call that Trump was “crazy.”

Even during Milley’s swing through Europe last week, headlines dogged him and reporters quizzed him. Mostly he batted questions away or buried them in detailed historical precedent.

Burly and square-jawed, with a bushy slash of eyebrows over often mischievous eyes, Milley is quick with a quip and frequently a curse. Born in a Boston suburb, Milley has Irish roots and an oversized personality that belies a sharp intellect and a penchant for digging deep into military history. The Princeton-educated Milley often meets simple questions with a deep dive into history that can reach as far back as the Greeks, cover long stretches of both world wars, and expound upon the context and concepts of war.

So as he faced accusations of disloyalty for what the book “Peril,” by Bob Woodward and Robert Costa, reported as assurances to a Chinese general that he would warn him of a U.S. attack, Milley gripped his identity as a soldier who answers to civilian leaders. He declined to make his case in the media, instead telling reporters that he will lay out his answers directly to Congress. His only brief comments have been that the calls with the Chinese were routine and within the duties and responsibilities of his job.

“I think it’s best that I reserve my comments on the record until I do that in front of the lawmakers who have the lawful responsibility to oversee the U.S. military,” Milley said. “I’ll go into any level of detail Congress wants to go into.”

While some in Congress have charged that he overstepped his authority, President Joe Biden has stood by him.

Loren Thompson, a longtime observer of the U.S. defense establishment as chief operating officer of the nonprofit Lexington Institute, says Milley is a victim of Washington’s extreme partisanship and perhaps of his own efforts to shape his public image.