It's going to be a very long summer. As House Speaker Nancy Pelosi's (D-Calif.) clashes with fellow Democrats continue to capture headlines, tensions are heating up on the Hill.

Recently, Justice Democrats, a progressive political action committee, announced their intention to back primary challenges against centrist Democrats, and not everyone is thrilled. On Friday, one senior Democratic source reportedly told Fox News' Brooke Singman the effort would be futile. "No one is afraid of those nerds," the source said. "They don't have the ability to primary anyone."

Justice Democrats was founded in early 2017, and is best known for endorsing and supporting the group of freshmen Democrats now known as "the Squad," which includes Reps. Alexandria Ocasio-Cortez (N.Y.), Ilhan Omar (Minn.), Rashida Tlaib (Mich.), and Ayanna Pressley (Mass.).

The simmering tensions between career Democrats and new recruits also flared up earlier this week, when Pelosi reportedly addressed congressional Democrats in a closed-door meeting, instructing them to "not tweet," and urging her colleagues to bring concerns directly to her instead of airing grievances online. "You got a complaint? You come and talk to me about it," Pelosi told Democrats, reported Politico.

Her message was interpreted by some as aimed at Ocasio-Cortez and the rest of "the Squad," although Pelosi's office maintains her comments were directed at all Democrats. Ocasio-Cortez shot back at Pelosi, criticizing her for what she called the "explicit singling out of newly elected women of color".

The irony of the senior Democratic source's anonymity notwithstanding, the "nerds" comment left many scratching their heads, mostly because Ocasio-Cortez primaried and won against ten-term incumbent Rep. Joe Crowley, and Pressley won a similar upset victory against ten-term incumbent Rep. Mike Capuano. Steven Orlofsky

Time has selected 16-year-old Swedish climate activist Greta Thunberg as its 2019 person of the year.

Thunberg, who this year led a worldwide movement demanding action on climate change and delivered a scathing United Nations speech scolding world leaders for "failing us," is the youngest Time person of the year ever by almost a decade; the previous youngest was 25-year-old Charles Lindbergh in 1927.

"For sounding the alarm about humanity’s predatory relationship with the only home we have, for bringing to a fragmented world a voice that transcends backgrounds and borders, for showing us all what it might look like when a new generation leads, Greta Thunberg is Time's 2019 Person of the Year," Time editor-in-chief Edward Felsenthal said.

The four other final candidates considered for person of the year were President Trump, House Speaker Nancy Pelosi (D-Calif.), the anonymous whistleblower whose complaint led to the impeachment inquiry, and the Hong Kong protesters. Brendan Morrow

Four more years? If former Vice President Joe Biden is elected, maybe not.

Biden is signaling to aides that he would not run for a second term should he be elected president, Politico reports, with a prominent adviser to the campaign telling the outlet, "he's going to be 82 years old in four years and he won't be running for re-election."

The former vice president's advisers have reportedly been debating whether he should make this pledge publicly, but Politico reports Biden "has for now settled on an alternative strategy: quietly indicate that he will almost certainly not" do so. Citing four people who regularly talk to Biden, Politico writes it's "virtually inconceivable" he would run for re-election.

Another Biden adviser suggested he's somewhat less definitive about it but has the attitude of, "I want to find a running mate I can turn things over to after four years but if that's not possible or doesn't happen then I'll run for re-election." This adviser added he will not make the pledge publicly, while another said he dismissed such a pledge as a "gimmick."

Still, Politico reports, "several advisers now quietly acknowledge that while Biden won't run for re-election he cannot say so publicly."

In April, Biden simply responded "no" when asked if he would only serve one term, but Politico notes that in October, he was less definitive about it.

"I feel good and all I can say is, watch me, you'll see," Biden said, The Associated Press reports. "It doesn't mean I would run a second term. I'm not going to make that judgment at this moment." Brendan Morrow

Wednesday is the final day of campaigning before Britain votes on a new Parliament, and though Prime Minister Boris Johnson's Conservatives have consistently led in the polls, "the size of the margin is seen as narrowing before Thursday's contest," The Associated Press reports. "All of the parties are nervous about the verdict of a volatile electorate weary after years of wrangling over Brexit — and likely to dump traditional party ties." Johnson's main opponent is Labour leader Jeremy Corbyn. Neither man is popular.

"Welcome to the 2019 general election, a pre-Christmas present few British voters seem anxious to unwrap," writes BBC North America reporter Anthony Zurcher. "It's as if the 2016 U.S. presidential election, where both major candidates were deemed flawed and untrustworthy, is playing itself out again three years later, on the other side of the Atlantic." Johnson, campaigning for a parliamentary majority to push Brexit through, faces serious questions about his honesty and trustworthiness. Corbyn is inconsistent on Brexit, vows to pull Britain to the left, and faces criticism that he ignored anti-Semitism in his party.

The election was supposed to be about Brexit, but on Monday, the Daily Mirror published a photo of a 4-year-old boy sleeping on the floor of a hospital in Leeds, the photo went viral, and suddenly the Conservatives' decade of cuts to the beloved National Health Service (NHS) was the top campaign issue. Johnson initially refused to look at the photo on an iTV reporter's phone, pocketing the reporter's phone and saying he would "study it later."

Another echo of 2016 is the apparently organized spread of misinformation via social media. Soon after the photo of the Leeds boy went viral, for example, a Facebook post took off claiming — falsely — that the photo was staged. "False stories are getting out there and exploding in social media," Matt Walsh, a researcher at the University of Cardiff, told AP, and they're "being put in the public domain through some very dark networks." Peter Weber

A federal judge in El Paso ruled Tuesday that President Trump can't use $3.6 billion in repurposed military constructions funds to build his Mexico border wall. The nationwide permanent injunction strips Trump of about a third of the $10 billion he has claimed for border barrier construction, specifically the funds Trump planned to use to build 175 miles of steel barriers. U.S. District Court Judge David Briones said Trump does not have the lawful authority to use the National Emergencies Act to sidestep Congress and reprogram money appropriated for different purposes. The Trump administration has signaled that it will appeal the decision by Briones, a Bill Clinton appointee. Peter Weber

House Speaker Nancy Pelosi (D-Calif) and President Trump agreed Tuesday that their final version of the U.S.-Mexico-Canada trade agreement (USMCA) is better than NAFTA and great for America. Pelosi and Senate Republicans also agreed that House Democrats had wrested significant concessions from Mexico and from the White House over months of tough negotiations. "We stayed on this, and we ate their lunch," Pelosi told fellow Democrats in a closed-door meeting Tuesday morning, according to Politico and The Washington Post.

"The deal didn't come easy — and it was on the brink of death multiple times over the past year," Politico reports. "Getting to yes required negotiations with an ideologically diverse coalition that included congressional Democrats, organized labor and Mexico's private sector, Canadian ministers, and Trump's hard-charging U.S. trade representative, Robert Lighthizer." Lighthizer started negotiating with Pelosi and nine hand-picked House Democrats over the summer, and the Democrats steadily won concessions on prescription drug patents, enforcement mechanisms, environmental protections, and — finally and crucially — labor.

Senate Republicans weren't thrilled when Lighthizer briefed some of them on the USMCA changes Tuesday morning, the Post reports. The negotiations "seemed to be a, you know, just a one-way direction in the direction of the Democrats," Sen. Pat Toomey (R-Pa.) told the Post. Sen. John Cornyn (R-Texas) said his "concern is that what the administration presented has now been moved demonstrably to Democrats, the direction they wanted. And anything that gets the AFL-CIO's endorsement ...  could be problematic."

The compromises on the revamped NAFTA pact "reflect Trump's eagerness to secure legislative accomplishments he can highlight during his 2020 presidential campaign, as well as the White House's confidence that it risks little backlash from a GOP increasingly molded in Trump's image," the Post reports. One GOP Senate aide told the Post that the Republicans "complaining they are not included are also too scared to vote against [Trump]. So why would he bother negotiating with them?" Peter Weber

"It is an historic day," Stephen Colbert said on Tuesday's Late Show. "For only the fourth time in American history, articles of impeachment were drafted against a sitting president." He explained the two articles and made a joke about President Trump only looking at "the impeachment centerfold." Some critics said Democrats should have waited until the courts forced Trump officials to defy Trump and testify, but Rep. Adam Schiff (D-Calif.) argued that waiting would let Trump "cheat just one more time."

"Fun fact," Colbert joked: "'Why Not Let Him Cheat Just One More Time?' was what Trump had inscribed on Melania's wedding gift."

"I know this sounds weird, but I'm actually proud of Donald Trump," Trevor Noah said at The Daily Show. "I didn't think he would make it three years. ... Trump getting this far into his presidency without being impeached is a lot like when a dog accidentally drives a car into a tree: Yeah, the dog crashed, but he made it like eight blocks!"

Democrats debated over how many articles of impeachment to draft, "but in the end they decided to strike with surgical precision" — and obvious restraint, Noah said. "The good news for Trump is that he's only facing two charges, although in a way that's also kind of sad for him. Because Nixon had three articles brought against him, Bill Clinton had four, and Andrew Johnson had 11, which means Trump will have the smallest impeachment of all time. You know that's going to make him insecure."

"Democrats are charging Trump with obstruction of Congress and abuse of power," Jimmy Kimmel said on Kimmel Live. "Who would have ever imagined that the guy who bragged about being able to walk in on contestants in his beauty pageant while they're changing clothes would abuse his power?" Trump and Senate Majority Leader Mitch McConnell (R-Ky.) have reportedly been arguing about how the inevitable Senate trial should go, he said, puzzled at why Trump gets any say: "The Republicans are screaming that the process is unfair as the defendant is telling them how long he wants the trial to last."

Harry Styles, standing in for James Cordon on The Late Late Show, noted Trump's complaints about impeachment and responded with an unsympathetic lyric to one of his songs. Watch below. Peter Weber