Washington (CNN) A new, critical Trump administration vacancy. A vexed VP. And the domino effects of the special counsel investigation.

It's all part of this week's "Inside Politics" forecast, where you get tomorrow's headlines today.

1) A frustrated Mike Pence

Mike Pence has been described by loyalists as frustrated by the drumbeat of bad news about his boss. And allies of the vice president have taken pains to suggest he was not involved when the Trump transition team and the White House made some bad calls about former National Security Adviser Michael Flynn.

It is déjà vu all over again.

While it is too soon to make any conclusions about the new special counsel probe into Trump's ties to Russia, history suggests that major, time-consuming investigations tend to expose tensions between the president and the vice president.

George H.W. Bush, for example, famously insisted he was "out of the loop" when the bad stuff that led to the Iran-Contra scandal happened.

The Monica Lewinsky scandal was the last straw for Vice President Al Gore.

And the Valerie Plame special counsel investigation that led to charges against Scooter Libby caused major strains between President George W. Bush and Vice President Dick Cheney, to whom Libby was a key confidante.

Again, too soon to know if the Trump-Pence relationship will fray during the current investigation. But the early signs of tension are a reminder history does repeat itself, and it's a subplot worth tracking.

2) Green light for Congressional investigations

One big question after the appointment of Special Counsel Robert Mueller to oversee the Russia election meddling investigation was whether it would force congressional investigations to dial back their work so as not to interfere.

That was a major focus of inquiry when the man who decided to name a special counsel, Deputy Attorney General Rod Rosenstein, met with lawmakers late last week.

Karen Tumulty of The Washington Post says lawmakers who expected they might be told to back off were instead given a green light.

"He encouraged them to go full speed ahead. He said as long as you've got a point of contact in the Justice Department, go for it," Tumulty said. "I think that is important, especially to these endangered Republicans. They really feel they cannot be seen as putting the brakes on this."

3) Capitol Hill turf battles

It was big news when former FBI Director James Comey agreed to testify at a public hearing of the Senate Intelligence Committee sometime soon after Memorial Day.

So why is Sen. Lindsey Graham not happy?

Welcome to Capitol Hill turf wars, says CNN's Manu Raju.

"This is part of an increasingly tense turf war between the Intelligence Committee and Judiciary Committee over getting access to information and documents," Raju explained. "The judiciary committee has oversight over the FBI and some of the members are not happy they have not gotten some information.

"This comes also as one of the chairman of the subcommittee on the Judiciary Committee, Senator Lindsey Graham, started to assert himself on the Russia probe. [Graham] heard from Sally Yates, and that actually undercut the House Intelligence Committee's effort to hear from Sally Yates."

4) Who to watch as investigations heat up

The Intelligence Committee hearings are the main event on the Senate side, and GOP worries about looking too close to the Trump White House seemed to add some urgency to the committee's work this past week.

As we enter the next chapter -- congressional oversight side by side with the special counsel investigation -- some senators will get more attention than others.

Carl Hulse of The New York Times offers a road map.

"There's a group of four Republican senators who have really shown determination," Hulse said. "They want to see this through. Roy Bunt is one of them; Susan Collins [also]. Roy Blunt says, you know, we want to be able to show people that we talked to everyone that we should have talked to and we've seen every document we should have seen. So (we'll see) how these Republicans are going to be working in this new environment."

5 Help wanted: new Census chief

No, the US Census isn't sexy.

But it impacts just about everything, from the allocation of federal funds to how many seats your state gets in the House of Representatives.

The big event for the Census Bureau is every 10 years -- and as 2020 draws closer there are important preparations already in the works.

Now Census Director John H. Thompson has announced he is leaving at the end of June, exacerbating a leadership vacuum at a critical moment.

CNN's Nia-Malika Henderson explains.

"One of the things to look for -- who gets this slot and what the budgeting is for the Census going forward because it is important, at least historically," Henderson said. "It's been important to ramp up the spending in this Census in advance of 2020."