Before the career diplomats working in Ukraine discovered a “highly irregular” power structure around President Trump determined to undermine and derail them, a Trump cabinet secretary said the same thing happened to him. Today, David J. Shulkin, former secretary of Veterans Affairs, speaks about his experience with “a dual path of decision making in the White House” and how falling out of favor with President Trump’s political appointees ended his tenure. Guest: David J. Shulkin, a former secretary of the Department of Veterans Affairs in the Trump administration. For more information on today’s episode, visit nytimes.com/thedaily.  Background listening and reading:Mr. Shulkin’s story matches a pattern described that career diplomats have described to the impeachment inquiry. Here’s a “Daily” episode about their testimony.Back channels to the White House are at the heart of the investigation.