President Trump said Tuesday he will not cooperate with the congressional impeachment inquiry, pushing the United States toward a constitutional crisis. The White House announced its decision in an eight-page letter addressed to House Democratic leaders, blasting the inquiry as partisan and unconstitutional.

The letter arrived just hours after the Trump administration ordered a key witness in the impeachment probe, Ambassador Gordon Sondland, not to appear for scheduled testimony on Capitol Hill. President Trump tweeted, “unfortunately he would be testifying before a totally compromised kangaroo court.” Text messages turned over to Congress reveal Sondland helped to mediate conversations between Ukrainian officials and Trump’s personal attorney, Rudy Giuliani, aimed at winning a promise by Ukraine’s president to investigate Joe Biden and his son in exchange for hundreds of millions of dollars of U.S. military aid that Trump had placed on hold.

On Capitol Hill, House Intelligence Committee Chair Adam Schiff said Tuesday Democrats would issue a subpoena ordering Sondland to appear before Congress and to hand over electronic messages related to the investigation. Schiff said the White House’s decision to stonewall the impeachment probe was further evidence of obstruction.

Rep. Adam Schiff: “This is one of the few impeachment inquiries in the history of our country. It goes to the core of whether the president abused his office to seek political help in his re-election campaign and did so to the detriment of our nation’s security, did so by effectively coercing a country that has been invaded by Russia to investigate a rival, and condition the relationship between this country and that country on whether they were willing to play ball.”

Turkey’s government says its troops are prepared for an imminent assault on Kurdish fighters in northern Syria, after President Trump ordered U.S. troops to fall back from their positions on the Turkish-Syrian border. Kurdish fighters said they’re bracing for a “humanitarian catastrophe,” saying in a statement, “This attack will spill the blood of thousands of innocent civilians because our border areas are overcrowded.” This follows warnings that former Kurdish allies of the U.S. who feel betrayed by President Trump will abandon thousands of prisoners captured during the U.S.-backed war against ISIS over the past two years.

Afghanistan’s national intelligence agency says a top al-Qaeda leader was killed last month in a joint U.S.-Afghan military operation that killed at least 40 civilians at a wedding party, including 12 children. Afghan officials said the September 23 attack in the Musa Qala district of Helmand province also left 22 Taliban supporters dead — among them, they claimed, was Asim Omar, who led al-Qaeda’s affiliate in the Indian subcontinent since its formation five years ago. A Taliban spokesperson rejected the claims, calling them propaganda aimed at covering up a massacre of civilians.

Congressional Democrats and Foreign Service workers are condemning the Trump administration’s plans to withdraw the U.S. from the Open Skies Treaty, which allows member states to carry out unarmed surveillance flights over each other’s territories to verify arms control agreements. In a letter to the White House Monday, House Foreign Affairs Committee Chair Eliot Engel warned any withdrawal would benefit Russia, which annexed Crimea after invading Ukraine in 2014. Congressmember Engel wrote, “Observation flights under the treaty have generated additional information regarding Russian military action in Ukraine and provided a check on further Russian aggression there.” This comes just two months after President Trump formally withdrew the U.S. from the Intermediate-Range Nuclear Forces Treaty with Russia, the landmark 1987 agreement banning all nuclear and non-nuclear missiles with short and medium ranges.

British officials are asking the Trump administration to reconsider granting diplomatic immunity to a U.S. suspect in the death of a 19-year-old motorcyclist. Harry Dunn died after he was struck by a car in late August near an Air Force base in central England. British police say U.S. citizen Anne Sacoolas had been driving on the wrong side of the road ahead of the crash. They say she fled the country after learning that Dunn had died. Sacoolas is the wife of a U.S. intelligence officer, and the State Department has argued she has full diplomatic immunity. Prime Minister Boris Johnson on Monday called on her to return to the U.K.

Prime Minister Boris Johnson: “I do not think that it can be right to use the process of diplomatic immunity for this type of purpose, and I hope that Anne Sacoolas will come back and will engage properly with the processes of laws that are carried out in this country.”

The Supreme Court heard oral arguments Tuesday in three cases that will determine whether LGBTQ people can be fired from their jobs due to their sexual orientation or gender identity. Among the court’s conservative justices, only Neil Gorsuch appeared open to prohibiting such workplace discrimination. Outside the court, plaintiff Aimee Stephens, who was fired from her job at a funeral home in 2013, joined a rally hosted by supporters. This is Laverne Cox, award-winning transgender actress.

Laverne Cox: “I hope, no matter what our justices decide, that Americans know that it should not be OK to discriminate against someone simply for being who they are. If we do not win this case, then the people, then our legislature needs to make it clear that discrimination against anyone because of who they are should not be the way that we live our lives here in the United States of America.”

The Supreme Court is expected to hand down its decision in the three cases by early next summer. We’ll have more on Tuesday’s action at the Supreme Court later in the broadcast. Click here to see our full interview with Laverne Cox.

California’s largest utility company, PG&E, says it’s begun shutting off electricity to 800,000 customers, as dry, windy conditions have increased the threat of wildfires in 34 of the state’s northern and central counties. The unprecedented blackouts follow last year’s devastating Camp Fire, which killed 85 people — the deadliest blaze in California history. Investigators found that poorly maintained PG&E transmission lines sparked that fire last November. Climate scientists say hotter and drier conditions across California due to rising greenhouse gas emissions have made wildfires more widespread and more intense.

Voters in Montgomery, Alabama, have elected an African-American mayor for the first time in the city’s history. Probate Judge Steven Reed captured two-thirds of ballots in a runoff election Tuesday. Montgomery was once the capital of the Confederacy. In the 1950s, it became the epicenter of the civil rights movement, as Rev. Martin Luther King Jr. and Rosa Parks led the successful Montgomery bus boycott to desegregate public transportation.

A new book offers chilling details about an incident that led NBC to fire “Today Show” host Matt Lauer in 2017. Journalist Ronan Farrow writes in his new book, “Catch and Kill,” that Lauer raped NBC producer Brooke Nevils in a hotel room in Sochi, Russia, in 2014, as they covered the Winter Olympics. Nevils called the incident “excruciatingly painful” and said it left her bleeding for days. Multiple other women have accused Matt Lauer of sex crimes. The New York Times reports one former NBC employee was summoned by Lauer to his office in 2001, where he allegedly locked the door and sexually assaulted her until she passed out.

A new analysis finds the wealthiest 400 families paid a lower share of the U.S. tax burden last year than people in any other income group. The finding comes from new research by UC Berkeley economists Emmanuel Saez and Gabriel Zucman in their forthcoming book, “The Triumph of Injustice: How the Rich Dodge Taxes and How to Make Them Pay.” A dramatic animated graph of the researchers’ data produced by The New York Times shows the U.S. tax system becoming far less progressive over seven decades. In 1950, the total tax rate for the wealthiest 400 families stood at 70%; after President Trump’s tax cuts for the wealthy took effect, the tax rate on U.S. billionaires had fallen to just 23%.

Vermont senator and 2020 presidential hopeful Bernie Sanders said Tuesday he will scale back the number of campaign events he participates in as he recovers from a heart attack he suffered last week at a rally in Las Vegas. Sanders says he still plans to join an October 15 televised debate of the top 12 Democratic candidates. Over the weekend, Sanders’s daughter-in-law, Rainè Riggs, died of neuroendocrine cancer — just two days after her diagnosis. Riggs, who was married to Senator Sanders’ son Levi, was just 46 years old.

In Brazil, human rights groups are warning in an open letter that the Amazon’s last uncolonized indigenous people face “genocide” amid raging fires and mounting incursions into their territories. The warning comes after the government of far-right President Jair Bolsonaro abruptly fired the head of the government agency tasked with protecting uncontacted tribes. Brazil’s Indigenous Missionary Council warns the number of invasions of indigenous territories has doubled under Bolsonaro, with more than 150 such incidents since January. And there have been a record 87,000 forest fires in Brazil this year, according to official figures — many of them deliberately set to clear land. In a statement, the indigenous rights group Survival International said, “President Bolsonaro … wants to open up Indigenous territories across Brazil to loggers, miners and ranchers. He doesn’t care how many Indigenous people die in the process, and has openly expressed his racist contempt for them on many occasions.”

Pope Francis welcomed indigenous leaders from Amazonia to the Vatican for a gathering of bishops known as a “synod.” The three-week meeting will focus on the Catholic Church’s efforts to safeguard the Amazon region. This is Pope Francis speaking Sunday.

Pope Francis: “May God preserve us from the greed of new forms of colonialism. The fire set by interests that destroy, like the fire that recently devastated Amazonia, is not the fire of the Gospel.”

A massive oil slick has fouled more than 900 miles of shoreline along Brazil’s northeastern coast, affecting 46 cities and some of South America’s most popular beaches. Brazil’s environmental agency says tests of the oil show it’s not of Brazilian origin. The source of the crude oil remains unknown.

In Canada, Prime Minister Justin Trudeau says he will appeal a court ruling from September that found indigenous youth were “willfully and recklessly” harmed under Canadian child welfare policies. The appeal could block some 2 billion Canadian dollars’ worth of reparations for at least 50,000 indigenous youth who were removed from their homes as children and impacted by the severe underfunding of federal child welfare programs for the indigenous community. The Canadian Human Rights Tribunal ruled last month the federal government had purposely discriminated against indigenous youth, and ordered the government to pay $40,000 Canadian dollars to each child who was removed from their homes.

A study by the University of New Mexico found that hundreds of Navajo women presented alarming levels of uranium in their systems — even decades after mining of the radioactive metal ended on their reservation. Of nearly 800 Navajo women who were part of the federally funded study, at least one-quarter tested positive for high levels of uranium. A group of babies also showed uranium levels far higher than the national average. New Mexico Congressmember Deb Haaland and other Democrats are pushing for legislation to expand compensation to people exposed to uranium.

Sixteen-year-old Swedish climate activist Greta Thunberg met with indigenous youth climate leaders Tuesday as she visited the Standing Rock Sioux Reservation in North Dakota. Thunberg was welcomed by 16-year-old high school junior Tokata Iron Eyes, who was just 12 years old when she joined protests against the Dakota Access pipeline in 2016. Iron Eyes later appeared with Greta Thunberg in a video produced by the Lakota People’s Law Project urging Congress to stop the Keystone XL pipeline.

Tokata Iron Eyes: “Indigenous peoples have been on the frontlines of the climate crisis, and we know how to live in balance with the Earth. And so, when we’re talking about solutions, we have to include indigenous peoples in the conversation. So, let’s protect our indigenous peoples, their rights, their communities, their way of life, because that’s what we’re going to need when we go into this battle.”