President Trump's new personal attorney, Rudy Giuliani, told reporters Saturday his client is "committed to regime change" in Iran, which Giuliani cast as a way to make Tehran a U.S. and Israeli ally. Trump suggested as much on Twitter in December, responding to news of anti-government protests in Iran by saying "Iran is failing at every level" and it is "TIME FOR CHANGE!" He did not specify whether he meant forcible, U.S.-led regime change, like that in Iraq and Libya.

The United States' last round of regime change in Iran — the 1953 CIA-orchestrated coup that ousted a democratic government; installed a pro-U.S. monarch; and set in motion the events that created the present Iranian government — is the basis for poor U.S.-Iran relations to this day.

Tehran, meanwhile, issued a warning Saturday against U.S. withdrawal from the Iran nuclear deal, which Trump has threatened. "If America leaves the nuclear deal, this will entail historic regret for it," said Iranian President Hassan Rouhani. "We have plans to resist any decision by Trump on the nuclear accord," he continued. "Orders have been issued to our atomic energy organization ... and to the economic sector to confront America's plots against our country."

Did you know Joe Biden takes the Amtrak?

Just a few hours after the former vice president announced his candidacy for president, he was already spotted back aboard his favorite mode of transportation. America's top train line has been as constant in Biden's life as presidential campaigns, and, unsurprisingly, it's already a big part of his 2020 one.

Biden got his public transportation reputation back in his senatorial days, riding the train back and forth between his family in Delaware and Capitol Hill every day. He even took the Amtrak home after President Trump's inauguration in 2017. Now, the train has yet again pulled back into Biden's station, both in reality and in a very prominent place on Biden's campaign website. Kathryn Krawczyk

Fox News legal analyst Andrew Napolitano is blasting President Trump over Special Counsel Robert Mueller's report, suggesting it proves he obstructed justice numerous times.

Napolitano in an op-ed for Fox News wrote that Mueller's report includes "at least a half-dozen crimes of obstruction committed by Trump," including Trump allegedly asking his White House counsel to fire Mueller, something Trump has denied doing. "That's obstruction of justice," Napolitano definitively and repeatedly states in a video after running through a number of incidents described in the Mueller report.

The Fox News analyst subsequently rips into the president for this behavior, writing, "ordering obstruction to save himself from the consequences of his own behavior is unlawful, defenseless and condemnable."

Napolitano also takes issue with Attorney General William Barr, saying he is "wrong" that a person can't be guilty of obstruction if they aren't guilty of the underlying crime being investigated. Instead, Napolitano says, the "nearly universal view of law enforcement" is that any attempted interference with an investigation is obstruction, and the obstruction doesn't have to be successful to be unlawful.

Napolitano summarized the situation in a video by saying that the report concludes that Trump "probably committed the crimes of obstruction of justice but probably should not be charged for them," which he calls a "head-scratcher." The question now, Napolitano writes in his op-ed, is whether Democrats will "utilize Mueller's evidence of obstruction for impeachment." Brendan Morrow

Joe Biden is already proving President Trump's "Sleepy Joe" nickname wrong.

After months full of teases, the former vice president launched his presidential campaign on Thursday with a video tweeted at an absurdly early 6:00 a.m. ET. Sure, most of America was probably still in bed, but that's just what makes Biden's timing a shrewd, agenda-setting move.

With reports already indicating that Biden would announce Thursday, it made sense that he would ditch any pretenses and get the big news out first thing. That timing meant Biden dominated news alerts and publications' morning newsletters, and that he secured a top trending spot on Twitter even as the midwest was still waking up. It also meant Biden slid right into Trump's typical morning tweet storm, which goes on to suggest the president sees him as a threat. Perhaps Biden even took a cue from Trump in that respect, seeing as what the president tweets during his early executive time often dominates the news cycle all day.

Before Biden, Sen. Bernie Sanders (I-Vt.) had the earliest announcement video drop at 7:02 a.m ET. He's also — though probably unrelatedly — falling into second place behind Biden in most polls. Sens. Cory Booker (D-N.J.), Elizabeth Warren (D-Mass.), and Kamala Harris (D-Calif.) also shared announcement videos in the 7 a.m. hour. Sen. Amy Klobuchar (D-Minn.) and Pete Buttigieg, meanwhile, gave in-person speaking announcements in reasonable mid-afternoon time slots.

Sen. Kirsten Gillibrand (D-N.Y.) and Rep. Eric Swalwell (D-Calif.) secured some of the latest announcement times, both revealing their runs around 7 p.m. ET on The Late Show with Stephen Colbert. Former congressmember Beto O'Rourke also came in pretty late, spoiling his formal morning announcement with a text to a TV station the night before. Maybe, just maybe, that could play into why his campaign has stalled in the month since. Kathryn Krawczyk

Will the media make the same mistake with Joe Biden as it did with President Trump in 2016?

FiveThirtyEight's Nate Silver wondered as much on Thursday after Biden officially entered the 2020 race. The statistician and election expert writes that "there's a case to be made" that the media is "overlooking the obvious front-runner in Biden," instead chasing "shiny new objects like Pete Buttigieg" and ignoring "older, more working-class and more moderate Democrats."

Silver suggests media elites might have the "same blind spots for Biden that they had for Trump," meaning that although "journalists' social circles" may not be chock-full of Biden voters, "that doesn't mean they aren't out there." The fact that Biden's poll numbers have been largely unaffected by accusations of inappropriate touching also suggests "it's possible that the media is underestimating how robust Biden's support might turn out to be," Silver says.

This isn't to say that Silver sees Biden as a shoo-in for the Democratic nomination, though. He refers to Biden as an "underdog" in the field and points out a number of potential liabilities, including his age. Unfriendly media coverage could also hurt Biden, Silver believes, as his candidacy will be seen within the mainstream media as "boring and anticlimactic."

Still, Silver assesses that while Biden is not the "odds-on favorite," he is the race's front-runner, and he has clear paths to the nomination before him. Read Silver's analysis of Biden's 2020 chances at FiveThirtyEight. Brendan Morrow

North Korean leader Kim Jong Un met with Russian President Vladimir Putin on an island off Vladivostok, Russia, on Thursday for their first summit, Reuters reports. Kim arrived Wednesday in an armored train after saying during a stop en route that he hoped he and Putin could "discuss concrete questions about peace negotiations on the Korean peninsula, and our bilateral relations." Putin said he and Kim discussed the situation on the Korean Peninsula.

Kim wants to denuclearize, Putin said, but he needs "security guarantees" before he can do it. The meeting came after Kim's second summit with President Trump collapsed without a deal on denuclearization, leaving Trump's push for diplomatic progress with Pyongyang in limbo. Harold Maass

President Trump has offered a not-so-warm welcome to his possible 2020 opponent.

After former Vice President Joe Biden officially announced his presidential campaign on Thursday, Trump wasted little time in going on the offensive, tweeting that it has long been in doubt whether Biden has the intelligence to wage a successful primary campaign.

Once again, Trump also used the nickname "Sleepy Joe" and warned Biden the 2020 race will be nasty because he'll be "dealing with people who truly have some very sick and demented ideas."

In the months leading up to Biden's announcement, Trump viewed him as his "most formidable" potential opponent, Politico reported in February. But Trump's aides have reportedly assured him that Biden isn't a threat and probably won't make it through the Democratic primaries. Trump has said publicly that he would love to run against Biden, saying in 2018 that doing so would be "a dream."

Biden in his announcement video on Thursday went directly after Trump for his response to the 2017 Charlottesville protests, saying that if Trump is re-elected, "he will forever and fundamentally alter the character of this nation." Brendan Morrow