First Read is your briefing from Meet the Press and the NBC Political Unit on the day's most important political stories and why they matter.

Trump’s guiding principle so far has been undoing Obama’s agenda

President Trump is expected to announce at 3:00 pm ET that he is withdrawing from the Paris climate agreement (although perhaps with some exceptions — so maybe it’s not a full pullout), an administration official tells NBC’s Kristen Welker. And with that decision to withdraw, it’s hard not to conclude that the guiding philosophy of Trump’s first four months in office has been to rollback Barack Obama’s agenda — or do what Obama refused to do. Think about it:

He’s pushed to repeal and replace the Affordable Care Act;

He took limited military action against Syria for using chemical weapons;

He withdrew from the Trans Pacific Partnership trade agreement;

He’s expected to reverse Obama’s open policies toward Cuba;

And today, it looks like a foregone conclusion that he’s withdrawing from the Paris agreement.

Yes, Trump campaigned on many of these positions (although the military action in Syria contradicted what he had said in the past on the issue). And yes, all new presidents who hail from a different political party typically break — in one way or another — from their predecessors.

But what’s different about Trump’s breaks with Obama is that he really hasn’t outlined a better way forward. On health care, despite the House’s passage of its repeal-and-replace legislation, Trump tweeted yesterday: “Hopefully Republican Senators, good people all, can quickly get together and pass a new (repeal & replace) HEALTHCARE bill. Add saved $'s.” (That doesn’t sound like someone enamored with the House bill.) On Syria, there’s still isn’t a defined policy how to deal with Assad. On trade, Trump hasn’t found a way to assert more influence in Asia. On Cuba, he hasn’t announced an alternative, especially with some of his advisers acknowledging that the open policies have improved on the old Cold War dynamic. And on the Paris agreement, what’s a better way to ensure the rest of the world is committed to improving the environment? These anti-Obama actions have been mostly symbolic. But what’s been missing is a clear alternative — other than just going back to where things were before 2009.

So what happens if Trump leaves the Paris climate agreement?

NBC's Benjy Sarlin: “The agreement, which is not a binding treaty, calls on countries to make voluntary national pledges to reduce emissions and provide periodic updates on their progress. President Barack Obama committed America to a goal of lowering emissions by 26 percent to 28 percent below 2005 levels by 2025. These targets aren't fixed forever, though, and the broad aim is to increase them over time.” So what happens if Trump withdraws? “The agreement won't fall apart overnight. Already, reports suggest China and the European Union are prepared to publicly recommit to the agreement with or without the United States. Some experts say China appears to be reducing emissions ahead of schedule, in part because the country is phasing out coal quicker to reduce choking smog in its major cities. Trump also can't technically withdraw from the agreement until November 2019. It's possible he could speed things up by abandoning the underlying Senate-approved climate treaty that the agreement is linked to.”

It looks like the Trump administration will return those Maryland and New York compounds back to Russia

Speaking of Trump breaking with Obama, here’s what the Washington Post reported last night: “The Trump administration is moving toward handing back to Russia two diplomatic compounds, near New York City and on Maryland’s Eastern Shore, that its officials were ejected from in late December as punishment for Moscow’s interference in the 2016 presidential election... Early last month, the Trump administration told the Russians that it would consider turning the properties back over to them if Moscow would lift its freeze, imposed in 2014 in retaliation for U.S. sanctions related to Ukraine, on construction of a new U.S. consulate on a certain parcel of land in St. Petersburg. Two days later, the U.S. position changed. Secretary of State Rex Tillerson told Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak at a meeting in Washington that the United States had dropped any linkage between the compounds and the consulate, according to several people with knowledge of the exchanges.”

How Trump’s Russia controversy has progressed much faster than Bill Clinton’s Whitewater

Although they’re not quite apples-to-apples comparisons, Trump’s Russia controversy and Bill Clinton’s Whitewater both saw their origins in the previously conducted presidential election. But consider how much FASTER Trump’s Russia situation has progressed than Whitewater did, at least when it comes to these four developments below:

FIRST RECUSAL

Russia probe: March 2, 2017 (Trump time in office: About 6 weeks): Attorney General Jeff Sessions recuses himself from any federal inquiries involving Trump's 2016 campaign.

Whitewater: Nov. 9, 1993 (Clinton time in office: About 10 months): U.S. Attorney Paula Casey asks to be recused from the investigation because of her family’s connections to the Clintons; Donald B. Mackay takes over the probe

FIRST MAJOR RESIGNATION AS A RESULT OF THE CONTROVERSY

Russia probe: Feb. 13, 2017 (Trump time in office: 3 weeks): National Security Adviser Michael Flynn resigns after revelations that he misled the vice president and other officials about his conversations with the Russian ambassador

Whitewater: March 5, 1994 (Clinton time in office: 13.5 months): White House Counsel Bernard Nussbaum resigns under fire after revelations that he met privately with Treasury officials to discuss the Whitewater probe

SPECIAL COUNSEL PICKED

Russia probe: May 17, 2017: (Trump time in office: 4 months): Deputy AG Rod Rosenstein names former FBI Director Robert Mueller III as special counsel

Whitewater: Jan. 20, 1994: (Clinton time in office: one year): Janet Reno picks former U.S. Attorney Robert Fiske Jr. as special counsel.

PRESIDENT RETAINS AN OUTSIDE LAWYER

Russia probe: May 23, 2017: (Trump time in office: 4 months): Trump retains Marc E. Kasowitz to help with Russia investigation

Whitewater: November 1993 (Clinton time in office: About 9 months): Clinton retains David Kendall to help with Whitewater investigation

Comey “is cleared for takeoff” to testify next week

Per NBC’s Ken Dilanian, former FBI Director James Comey has spoken with special counsel Bob Mueller, and has been cleared for public testimony as soon as next week. Comey “is cleared for takeoff,” Dilanian was told by a source close to Comey. But will Trump exert executive privilege to stop Comey’s testimony? “Courts have recognized a president’s constitutional right to keep his discussions a secret in most instances,” the New York Times writes. “A White House spokeswoman had no comment on whether Mr. Trump planned to try to block Mr. Comey’s testimony. It is a delicate decision with political and legal consequences. ‘If they claim executive privilege, politically it gives the appearance that there’s something to hide, which just amplifies all the criticism,’ said Mark J. Rozell, a George Mason University professor and the author of a book on the history of executive privilege.”

2016 just won’t go away

The 2016 presidential election ended nearly SEVEN months ago, but it seems we’re all still trapped in it. Just consider yesterday: Hillary Clinton was continuing to re-litigate her defeat; Trump fired back on Twitter, calling her (again) “Crooked Hillary”; and former Vice President Joe Biden launched a new political action committee, per NBC’s Alex Seitz-Wald. As for Clinton, it’s worth noting how polarizing she’s still viewed -- commentators rolled their eyes at her explanation for her defeat, while others maintain that’s an example of the misogyny she faced. As for Trump, it’s still amazing how the victor can’t move on.

And as for Biden and a possible 2020 run, there are two ways it could go for him: Either he dies from a thousand different cuts (poor fundraiser, trade support, banking/credit-card company ties, 1994 crime bill, Anita Hill), or he’s truly a white knight for the party.