The Note: Comey saga gets new players Jeff Sessions is set to testify before the Senate Judiciary Committee Tuesday.

 -- WHAT YOU NEED TO KNOW TODAY

It's a date – but maybe just a first one. Attorney General Jeff Sessions pulls up a fast-warming chair Tuesday as he's set to testify before the Senate Intelligence Committee. But will the hearing be open or closed?

The attorneys general of DC and Maryland will file a lawsuit later today against President Trump, alleging he violated the Constitution by allowing his businesses to accept payments from foreign governments.

Trump warpath, part one: The president has set a hard deadline of July 4 for chief of staff Reince Priebus to clean house, Politico reports.

Trump warpath, part two: The president tweeted Sunday that he believes the "James Comey leaks will be far more prevalent than anyone ever thought possible. Totally illegal? Very ‘cowardly!'"

Former New York U.S. Attorney Preet Bharara said on "This Week" that, before being fired by Trump, he had been uncomfortable in his interactions with the president. He added that "there's absolutely evidence to begin a case" for obstruction of justice against President Trump.

THE TAKE with ABC News' Rick Klein

Things are going in the wrong direction if the idea is to change the subject. James Comey's testimony raised new questions rather than answering old ones for President Trump. And that was before Trump began to unload on "cowardly" Comey, and before Donald Trump Jr. was distinctly unhelpful to his father's cause. Questions abound for an even wider circle of Trump associates: Attorney General Jeff Sessions has earned himself just the first of several hot-seat days, and Don Jr. may have ensured himself his own invitations by appearing to back up Comey's account more than his father's. The president now has an open invite to testify under oath in front of senators. (We'll see if "100 percent" includes wiggle room.) There's still the matter of supposed tapes. (How short is the time period covered by, "you'll know shortly.") Critically, Trump is at war with a former FBI director. For all those implicated along with him in the story, it's not even clear how much of an army he has behind him in that battle.

THE GOP'S OPTIMISTIC WING

With all the scandals and accusations swirling around this White House, it would hardly be surprising if the Republican Party was starting to fracture -- but it isn't, at least based on one influential sample of establishment sentiment over the weekend. Some of the most vocal, Republican critics of President Trump were gathered in Utah and instead of bashing the White House, powerhouses like Mitt Romney and Sens. Lindsey Graham and John McCain backed it. Sure, they had stern advice for the man in the Oval Office -- do something to punish Russia, send a message to allies, stop tweeting -- they all said. But by and large, the men worked hard to tell their friends they were still cautiously optimistic things would get done in D.C. and despite what they called "theater" and "clutter," they wanted to help Trump succeed. On the Democratic side, a stark contrast unfolded simultaneously this weekend. Despite Democrats total lack of power in Washington, thousands of progressives came to strategize and organize around their far left policy ideals for a summit in Chicago. They listened to their hero, Sen. Bernie Sanders, talk at length about the ongoing failure and flaws of the Democratic Party. Folks reportedly floated the idea of a third party at a time when Democrats are trying to rebuild and plot ways to win back congressional seats, ABC News' MaryAlice Parks reports.

QUOTE OF THE DAY

"So [Trump] called me in December, ostensibly just to shoot the breeze and asked me how I was doing and wanted to make sure I was OK," former U.S. Attorney Preet Bharara said on "This Week"

WHAT TO WATCH TODAY

First daughter Ivanka Trump will be interviewed on "Fox and Friends" at 7 a.m. prior to her leadership of "workforce development week" in the coming days.

At the White House, President Trump will receive a National Security Council briefing this morning and meets with his Cabinet.

Sean Spicer briefs the press at 1:30 p.m..

NEED TO READ with ABC News' Adam Kelsey

Trump lawyer ''not going to speculate'' on whether the president might fire special counsel. A member of President Trump's personal legal team said he is "not going to speculate" on whether the president may order the firing of the special counsel investigating Russia's meddling in the 2016 election. But lawyer Jay Sekulow added that he "can't imagine the issue is going to arise." "I'm not going to speculate on what [Trump] will or will not do," said Sekulow on "This Week." http://abcn.ws/2shtyQc

U.S. military carries out first offensive airstrike in Somalia under Trump's new authorities. The U.S. military has conducted its first offensive airstrike against the jihadist fundamentalist group al-Shabab in Somalia, targeting the group under the new authorities given by the Trump administration in March that allows offensive airstrikes. "On June 11, at approximately 2 a.m. eastern daylight time, the Department of Defense conducted a strike operation against al-Shabab in Somalia," said Dana White, the Pentagon's chief spokesperson in a statement. http://abcn.ws/2rf45H3

Donald Trump Jr. appears to contradict father's account of private Comey meeting. The president on Friday denied outright testimony by James Comey to Congress that Trump said he hoped the FBI chief could let go of the Flynn probe. But in a television appearance Saturday evening, Donald Trump Jr. appeared to contradict his father's flat-out denial. "When [President Trump] tells you to do something, guess what, there's no ambiguity in it," Trump Jr. said in an interview with Fox News' Jeanine Pirro. http://abcn.ws/2shrwzL

WHO'S TWEETING?

@FLOTUS: Looking forward to the memories we'll make in our new home! #Movingday

@amybwang: The first dance. The toasts. The cake-cutting. The...surprise appearance by President Trump? http://wapo.st/2tagsRl

@joshgerstein: Press/public locked out of @realDonaldTrump fundraiser for Rep. Tom Macarthur this afternoon. Allegedly $800k raised behind closed doors

@chrisdonovan: RNC Chair McDaniel: "the RNC is always going to defend the president"

@SenatorLeahy: 3) My mssg to AttyGen Sessions: Approps & Judiciary have oversight of DOJ. You need to testify before both in public. You can't run forever.

Editor’s note: A previous version of this story incorrectly identified the committee that will meet with Attorney General Jeff Sessions. He will appear Tuesday before the Senate Intelligence Committee.