While waiting for the arrival of three US citizens from captivity in North Korea at Joint Base Andrews early this morning, Mike Pence gave an interview to Andrea Mitchell. He was asked about the Mueller investigation:

“You know, our administration has been fully cooperating with the special counsel and we’ll continue to. What I think is that it’s been about a year since this investigation began,” the vice president told NBC News’ Andrea Mitchell. “We’ve fully cooperated in it and in the interest of the country, I think it’s time to wrap it up. And I would very respectfully encourage the special counsel and his team to bring their work to completion.”

https://youtu.be/WnrE4_Wg0FQ

To me, this is more significant than any number of Trump tweets. Pence has steered clear of the investigation, with good reason. Him weighing in now is a hint that the White House has a pretty good idea of what Mueller has found and, more importantly, what he has not found. It is also a sign, along with Rosenstein getting rolled by the White House on another of Nunes’ document requests, that the White House is feeling confident about where it stands. When read in context with Trump’s “witch hunt” tweets and CBS polling which shows over half of Americans believe Mueller’s investigation is politically driven, I think the White House is sending a clear message that they cooperated in the past but unless they get something that indicates the Russian collusion part of the investigation is at an end, Mueller should expect to have a lot of resistance in the future.