Cindy McCain endorsed Democratic presidential nominee Joe Biden on Tuesday night, saying that there is "only one candidate in this race who stands up for our values as a nation, and that is Joe Biden."

Earlier in the evening, Biden announced during a virtual fundraiser that McCain, the widow of Sen. John McCain (R-Ariz.), decided to endorse him after it was reported by multiple news organizations that President Trump called U.S. soldiers who died in combat "losers" and "suckers;" Trump has denied making the comments. John McCain was a U.S. Navy officer and prisoner of war in Vietnam, and three of his children also served in the military.

Over a series of tweets, Cindy McCain explained why she is backing Biden. "My husband John lived by a code: Country first," she said. "We are Republicans, yes, but Americans foremost. There's only one candidate in this race who stands up for our values as a nation, and that is Joe Biden."

McCain went on to say that they "don't always agree on the issues, and I know he and John certainly had some passionate arguments, but he is a good and honest man. He will lead us with dignity. He will be a commander in chief that the finest fighting force in the history of the world can depend on, because he knows what it is like to send a child off to fight." Biden's son Beau, who died of brain cancer in 2015, was a member of the Delaware Army National Guard who served in Iraq. Catherine Garcia

"There is simply no democratic justification whatsoever for [U.K. Prime Minister] Boris Johnson or anyone else seeking to block the right of the people of Scotland to choose our future," Scottish National Party leader and Scotland's First Minister Nicola Sturgeon said Saturday in a victory speech after the SNP won its fourth straight election, while the pro-independence Greens also had a strong showing, meaning a majority of Scottish parliament would back a referendum.

If a vote is blocked Sturgeon added, it "will demonstrate conclusively that the U.K. is not a partnership of equals and astonishingly that Westminster no longer sees it as a voluntary union of nations."

While Sturgeon is expected to pressure Johnson to allow another referendum, the prime minister has said he won't, calling it "irresponsible and reckless."

As for what's happening on the ground with Scottish voters, Prof. John Curtice, whom Bloomberg notes is the U.K.'s "most prominent electoral analyst," said the country is "divided straight down the middle on the constitutional question," which was the driving force behind the highest turnout since 1999. There's no telling which way a vote would go at the moment, so a referendum would be an "enormous political gamble" for both Johnson and Sturgeon, Curtice writes. Read more at BBC and Bloomberg. Tim O'Donnell

Annie Pforzheimer, a longtime diplomat who has extensive experience working in Afghanistan, is concerned about President Biden's plan to withdraw U.S. troops from the country without any conditions from the Taliban by or before Sept. 11, 2021. In a piece for Politico published Saturday, she shares her not uncommon view that the U.S. exit will allow the Taliban an opportunity to "increase their territorial control and dictatorial rule," depriving Afghanistan of much hope for a "normal future." But, at this point, she acknowledges Biden's mind won't change, so she turned her attention to ways the U.S. can employ leverage without forces on the ground.

Pforzheimer's ideas include remaining publicly committed to Afghan security forces, retaining old and imposing new sanctions on the Taliban until they're no longer a threat to Afghanistan's stability, and refusing to recognize a Taliban government if it "denies basic human rights to its citizens." She also argues the U.S. should make sure that "Afghanistan's neighbors, particularly Pakistan and Central Asia ... prioritize their existing trade and energy linkages and press for a peace process that will contribute to regional prosperity." Additionally, she writes, "the Gulf States and other former and current Taliban patrons should understand that a peaceful outcome is a top U.S. government goal." Read Pforzheimer's full piece at Politico. Tim O'Donnell

The Colonial Pipeline, the principal transporter of gasoline and diesel fuel up and down the East Coast of the United States, was temporarily shut down on Friday after its operator, Colonial Pipeline Co., learned it was the victim of a cyberattack.

The attack reportedly involved ransomware and appeared to be limited to information systems, as opposed to operational control systems, but the investigation is still in the early stages. Subsequently, there's no clear sense of who the perpetrator was.

Analysts don't expect the stoppage to negatively affect fuel markets or cause any shortages, so long as it only lasts for a day or two, The Wall Street Journal reports. Still, Tom Kloza, the global head of energy analysis for Oil Price Information Services, told the Journal that targeting the pipeline, which carries roughly 45 percent of the fuel consumed in the United States, is a "big deal" and "could really wreak havoc."

Mike Chapple, a cybersecurity expert at the University of Notre Dame and a former National Security Agency official, added that the pipeline shutdown "sends the message that core elements of our infrastructure continue to be vulnerable to cyberattack," a threat Homeland Security Secretary Alejandro Mayorakas acknowledged as recently as Wednesday, the Journal notes. Read more at The Wall Street Journal and Bloomberg. Tim O'Donnell

The National Republican Congressional Committee did not share internal polling data that showed former President Donald Trump has weak numbers in key battleground districts at a retreat for House Republicans in April, two people familiar with the presentation told The Washington Post. The NRCC staffers reportedly held back the information even when a member of Congress asked them directly about Trump's support.

The Post later obtained the full polling results, reporting that Trump's unfavorable ratings were 15 points higher than his favorable ones, and nearly twice as many voters had a strongly unfavorable view of him than those who had a strongly favorable one. In those same districts, President Biden and Vice President Kamala Harris were both more popular than Trump, the Post notes.

It reportedly wasn't the first time this has happened — Rep. Liz Cheney (R-Wyo.) told colleagues that Republican campaign officials had also glossed over poor Trump polling during a retreat for ranking committee chairs in March, per the Post.

Cheney, you may have heard in recent weeks, is determined to move the GOP away from Trump and she'd likely point to the polling as a reason why, but she's faced a lot of criticism from her colleagues, including House Minority Leader Kevin McCarthy (R-Calif.), who think the party's short-term electoral chances are doomed without the former president leading the charge, and there's no indication their minds will change anytime soon. Read more about Cheney's efforts at The Washington Post. Tim O'Donnell

The Centers for Disease Control and Prevention on Friday updated its public COVID-19 guidance to explicitly state that the coronavirus can be transmitted via aerosols — smaller respiratory particles that can float — that are inhaled at a distance greater than six feet from an infected person. The risk is higher while indoors, bringing ventilation practices to the forefront. The new language marks a change from the federal health agency's previous stance that transmission of the virus typically occurs through "close contact, not airborne transmission."

Infectious disease experts have warned that the CDC and the World Health Organization (which has also updated its guidance) were overlooking evidence of airborne transmission during the pandemic, The New York Times notes, and some have stressed the need for the CDC to strengthen its recommendations for preventing exposure to aerosolized virus, especially in indoor workplaces like meatpacking plants.

Good ventilation should be one of the primary things to focus on, Dr. David Michaels, an epidemiologist at George Washington School of Public Health and the head of the Occupation and Safety Health Administration during the Obama administration, told the Times. Dr. Linsey Marr, an aerosol expert at Virginia Tech, explained that "if you're in a poorly ventilated environment, virus is going to build up in the air, and everyone who's in that room is going to be exposed."

Sociologist Zeynep Tufekci, who has long been pushing for such a change, called it "one of the most crucial scientific advancements of the pandemic" that should provide a lot of clarity about what is and isn't safe going forward. Read her Twitter thread on the issue here and learn more at The New York Times. Tim O'Donnell

India recorded 4,187 new COVID-19 deaths in the last 24 hours, the government said Saturday, marking the first time the country, which is in the midst of a record-breaking surge of infections, has tallied 4,000 fatalities in a day. India's death toll, which has been questioned by health experts, officially sits at 238,270, the third highest in the world after the United States and Brazil.

India also added 401,078 cases on Saturday, a slight drop from the previous day, but the country's peak is not expected until the end of May. While cases appear to be stabilizing in large cities like Mumbai and New Delhi, the coronavirus is spreading in rural areas and southern states, several of which have ordered lockdowns. Oxygen and critical care bed shortages remain a major concern. Read more at Al Jazeera and Agence France-Presse. Tim O'Donnell