U.N. Ambassador Nikki Haley shocked everyone on Tuesday — reportedly even top White House officials — when she revealed she was resigning. Even more surprising? President Trump may have kept Haley's resignation letter under wraps for nearly a week.

Haley confirmed her departure alongside Trump in a public Oval Office meeting on Tuesday, shortly after Axios reported she'd be leaving. It was an unexpected move for one of the more popular members of Trump's Cabinet, especially since rumors of administration resignations often swirl long before they actually happen.

Yet in the meeting, Trump said Haley told him six months ago she'd like to "take a break" at the end of the year. And Haley's resignation latter, later published by The Washington Post, is dated Oct. 3. In a White House known for leaks, "that is an eternity to keep [something] secret," Saagar Enjeti, a writer for the conservative website The Daily Caller, pointed out. Oct. 3 is also the same day Trump and Haley last met in the Oval Office.

The letter also reaffirms one highlight of Haley's Tuesday announcement: that she won't run for president in 2020. Haley repeatedly writes that she will "become a private citizen" following her resignation, though she will "continue to speak out from time to time on important public policy matters." She then goes on to liken her resignation to a "term limit" in the letter, saying "rotation in office benefits the public," and confirms she will serve until the beginning of next year.

Read the whole letter below. Kathryn Krawczyk

At least 18 people were killed and 57 injured Saturday during a suicide bombing in Kabul, Afghanistan, the interior ministry said. The casualty toll may continue to rise as family members continue searching hospitals where the wounded are being treated.

The explosion occurred outside an education center in Dasht-e-Barchi, a heavily Shiite neighborhood in the western section of the capital, per The Associated Press. No group has claimed responsibility for the attack, and the Taliban — which has begun peace talks with the Afghan government amid an ongoing, decades-long conflict that has seen a recent surge in violence — rejected any involvement. The Islamic State said it was behind a similar attack that killed 34 students at an education center in 2018, but there has been no word from the militant group regarding the most recent incident.

Also on Saturday, one roadside bomb killed nine people in eastern Afghanistan, and a second killed two policemen after it struck their vehicle en route to the site of the first explosion. Again, no one claimed responsibility, although a spokesman for the provincial police claimed the Taliban had placed the explosives, AP reports. Read more at The Associated Press. Tim O'Donnell

In the latest episode of Pod Save America — a podcast hosted by several former Obama administration staffers — the Democratic presidential nominee, former Vice President Joe Biden, laid out what Politico described as "the most in-depth statement of priorities we've heard from" the candidate.

Biden, responding to the Republican Party's agenda for a second Trump administration term (which includes items focused on space exploration and a national high speed wireless network), said that, first and foremost, he's determined to "get control" of the coronavirus pandemic. Beyond that, though, he said he wants to invest in "real infrastructure," with a heavy focus on science and technology. "We used to invest a little over 2.6 percent of our GDP in research and science," Biden said. "It's now down to 0.6 percent ... We're going to make sure that we can compete with the rest of the world and lead the rest of the world."

The former vice president predicted that, through these renewed efforts, "we're going to cure cancer" while making strides in research on Alzheimer's and diabetes, among other diseases. He also described an aspect of his agriculture policy plan, which he said could make the industry the first in the U.S. to reach the net zero carbon emission threshold. Tim O'Donnell

The State Department on Friday temporarily halted "all training programs related to diversity and inclusion," Reuters reports.

Reuters obtained an internal cable detailing the decision, which was made in response to an executive order issued by President Trump in September forbidding federal agencies to teach "divisive concepts" such as the idea that the United States is "fundamentally racist or sexist." Before that, the White House Office of Management and Budget sent a memo telling government officials they couldn't use taxpayer money to fund sessions focused on subjects like critical race theory or white privilege. The Trump administration's efforts to cut back on such programs comes amid a nationwide debate about racial injustice in the U.S. — both contemporarily and historically — which was fueled in large part by protests against police brutality earlier this year.

The State Department cable said the pause will allow the OMB "to review program content." Per Reuters, a report from an independent federal watchdog released this year said "longstanding diversity issues exist" in the State Department, particularly in senior ranks. The report noted that the overall proportion of racial or ethnic minorities working at the agency has increased, but the proportions of Black and female employees have declined. Read more at Reuters. Tim O'Donnell

Coronavirus vaccine trials conducted by AstraZeneca and Johnson & Johnson are preparing to resume, the pharmaceutical companies said Friday.

Both studies were put on hold after two volunteers who enrolled in AstraZeneca's vaccine trial developed a possible neurological side effect, and another person who enrolled J&J's study reportedly suffered a stroke. AstraZeneca, which had already restarted its trial in other parts of the world, including the United Kingdom, South Africa, and Brazil, said independent monitoring committees and international regulators agreed it was safe to resume the trial in the U.S, as well. The Food and Drug Administration reportedly did not find the vaccine candidate to be responsible for the neurological symptoms, but the agency was also unable to definitively rule out a link.

Similarly, investigators concluded the J&J volunteer's illness did not appear to be related to the vaccine candidate, although there was "no clear cause" of the incident. Paul Stoffels, the chief scientific officer at J&J, told Stat News the company could begin enrolling patients for the vaccine study — the only major one to test just a single dose — again early next week. Read more at The Washington Post and The Wall Street Journal. Tim O'Donnell

President Trump on Saturday joined the more than 50 million Americans who have already cased their ballots ahead of Election Day on Nov. 3. The president, who spent Friday evening at his Mar-a-Lago resort in West Palm Beach, Florida, voted in-person early in the morning before getting ready to depart the Sunshine State for three campaign rallies in North Carolina, Wisconsin, and Ohio, all crucial battlegrounds.

After exiting the booth, Trump told reporters he was very impressed with how secure the voting process was, especially compared to mail-in voting, which has become a major point of contention between Republicans and Democrats due to the increase in absentee ballots nationwide in 2020 because of the coronavirus pandemic. There is no evidence of widespread voter fraud, but Trump has continually reiterated his belief that the system is vulnerable to it. "When you send in your ballot, it could never be secure like that," Trump said Saturday. (Observers pointed out that the president mailed in his Florida primary ballot in August amid his criticism.)

Trump ended his quick exchange with the press on a lighter note, declaring that he voted "for a guy named Trump." Tim O'Donnell

Polish President Andrzej Duda tested positive for the coronavirus Friday, a presidential minister said Saturday. Duda is the latest among a handful of world leaders, including President Trump, to contract the virus. He reportedly "feels good" and is in isolation. Poland's president guides foreign policy and signs legislation, but most duties designated for the office are ceremonial, and day-to-day governance is the responsibility of the prime minister.

Duda's positive test result comes amid a wave of infections in Poland, which saw low rates earlier this year when the virus first struck Europe. On Saturday, the country recorded 13,628 new COVID-19 cases and 179 deaths, marking new 24-hour highs since the pandemic began. The government imposed new restrictions Saturday that fall just short of a lockdown in the hopes of curbing the outbreak, The Associated Press reports.

The virus continues to surge in other European countries, as well, including the Czech Republic, Belgium, the Netherlands, Switzerland, and France. Those five countries currently have the highest rate of infection worldwide, CNN reports.

Italy and Spain, which were hit hard by the virus early in the pandemic, are also dealing with case increases. Several regions in Spain have announced new night curfews in the coming days, while the governor of Italy's Campania said he is imposing a regional lockdown "for 30 to 40 days" after the country reported a daily record of infections Friday. Read more at The Associated Press and CNN. Tim O'Donnell