Six Democrats will face off Tuesday night in the last primary debate before the Iowa caucuses.

The Des Moines Register and CNN will host the debate, which runs from 9–11 EST p.m. Tuesday and take places in Iowa. Debate contenders include former Vice President Joe Biden; former South Bend, Indiana, Mayor Pete Buttigieg; Sen. Amy Klobuchar (D-Minn.); Sen. Bernie Sanders (I-Vt.); billionaire Tom Steyer; and Sen. Elizabeth Warren (D-Mass.).

The debate comes after Sen. Cory Booker (D-N.J.) dropped out of the race earlier this week. And with entrepreneur Andrew Yang unable to meet the Democratic National Committee's polling, the remaining six contenders are all white.

Expect to see a recent spat between the Sanders and Warren campaigns highlighted Tuesday night, after Sanders was reported to have told Warren in a pre-presidential run meeting that a woman couldn't win a race against President Trump. Sanders denied saying that, but Warren disputed his account in a later statement.

Watch the debate live on CNN, or stream it at the Des Moines Register. Kathryn Krawczyk

Former Vice President Joe Biden, the presumptive Democratic presidential nominee, is scheduled to give his acceptance speech during the last act of the mostly-virtual Democratic National Convention next Thursday at 10 p.m. E.T.

Just a few hours before, though, President Trump is heading to Old Forge, Pennsylvania, to deliver his own remarks on "Joe Biden's record of failure," the president's re-election campaign announced Saturday.

The timing is clearly not a coincidence, but the location probably isn't either. Old Forge is just a few miles outside of Scranton, Pennsylvania, which happens to be Biden's birthplace and where he spent part of his childhood before his family moved to Delaware.

And, of course, Pennsylvania is a crucial swing state, which Trump narrowly won in 2016 and is in danger of relinquishing to his challenger in November. Tim O'Donnell

The Food and Drug Administration on Saturday issued an emergency use authorization for the SalivaDirect COVID-19 diagnostic test developed by the Yale School of Public Health.

The test, which processes saliva samples to rapidly determine whether a person is infected with the coronavirus and does not require any type of swab or specific collection device, could be one of the first "major game changers in fighting the pandemic," said Andy Slavitt, a former acting administrator of the Centers for Medicare and Medicaid Services under the Obama administration, in a Twitter thread.

For starters, the process should be a lot more comfortable for people. It doesn't, as Slavitt puts it, require sticking "something four inches up a kid's nostril." But besides being painless, it's affordable — the materials are about $4, Slavitt said, and even when adding the cost of labor and overhead, its development is still cheaper than current tests.

And, because it's cheap and has a fast turnaround time, people will likely be able to get tested more frequently, which will in turn increase diagnostic accuracy.

Slavitt believes all of these assets could especially come in handy for schools, universities, and office buildings which theoretically need to ramp up testing if they want to re-open safely. It could also encourage more asymptomatic people to get tested.

The final reason Slavitt has high praise for the test isn't about the science. Instead, he pointed out that Yale, in partnership with the NBA, developed the test without any intention of making a profit. Tim O'Donnell

As the relationship between the United States and China deteriorates, Beijing is looking to tone down its rhetoric and salvage something, The New York Times reports.

Recently, top Chinese diplomats, academics, and state-run media outlets have — publicly, at least — taken a more moderate stance and backed efforts to find a way to co-exist peacefully with the United States. "There's a reflection that we should not let nationalism or hotheadedness somehow kidnap our foreign policy," Xu Quinduo, a commentator for state-run broadcaster China Radio International, told the Times. "Tough rhetoric should not replace rational diplomacy."

There have been both fewer calls for China to challenge the U.S. military and direct attacks on President Trump, and the strategy seems to be backed up by actions, as well. Earlier this week, for instance, The South China Morning Post reported that Chinese troops were given orders not to escalate the situation in the disputed South China Sea, where both the U.S. and Chinese have upped their military operations. "China won't fire the first shot," Jin Canrong, an international studies professor at Renmin University, told the Times.

It's not all about the U.S., however. China has also strained its relations with neighboring India, the United Kingdom, Canada, and Australia of late. "Beijing's rhetoric appears aimed at defusing the global backlash its brash diplomacy and harsh policies have provoked," said Jessica Chen Weiss, an associate professor of government at Cornell University. Read more at The New York Times. Tim O'Donnell

Sen. Kamala Harris (D-Calif.), the presumptive Democratic vice presidential nominee, may already be playing a key role in shifting the crucial swing state of Florida toward her running mate and presumptive Democratic presidential nominee, former Vice President Joe Biden.

The choice of Harris, who is of both Jamaican and Indian descent, for the ticket has excited the oft-ignored Caribbean-American voting bloc, especially among the Black West Indian diaspora, Politico reports. "It's the pick that energizes us. It's the pick that's getting us motivated," said Karen Andre, one of Biden's top Florida advisers. Andre, who is of Haitian-American descent, said the campaign is preparing a "full 360 degree effort" to engage Caribbean-American voters with paid radio ads in Creole and English, as well as possibly having local radio hosts interview the potential vice president.

Andre told Politico her phone was "burning" with calls from Jamaican-Americans after the Harris announcement, but she added she's also "heard from Haiti, Trinidad, Barbados, Bahamas."

Like all voting groups, Caribbean-Americans are not a monolith, and not every voter of Jamaican or Haitian descent, for instance, will vote for the Biden-Harris ticket. But Hans Mardy, a Haitian-American Republican activist in Miami who is struggling to support Trump after he vulgarly insulted Haiti earlier in his tenure, said people of Haitian and Jamaican descent in South Florida "have a very tight connection," indicating the apparent excitement about the presumptive Democratic ticket could indeed be infectious within the community. Read more at Politico. Tim O'Donnell

After the United Nations Security Council on Friday resoundingly defeated U.S. efforts to extend a global arms embargo on Iran, Tehran basked in the outcome, while U.S. lawmakers and analysts viewed the result as an indictment of the Trump administration's foreign policy.

Iranian President Hassan Rouhani said Saturday that the U.S., which garnered the support of only the Dominican Republic among the 15-member council (which includes allies like France, Germany, and the United Kingdom), suffered a "humiliation," and a spokesperson for Iran's foreign ministry called it a historic failure that has led to Washington's isolation.

President Trump's critics consider it the latest example of his administration's failures regarding Iran under the leadership of Secretary of State Mike Pompeo. Nicholas Burns, a professor at Harvard University's John F. Kennedy School of Government, agreed with Tehran about the decision exemplifying Washington's increasing isolation on the international stage, arguing Trump's own mistakes gave Iran "a victory it does not deserve" after his predecessors "unified the world against" the country. And Sen. Chris Murphy (D-Conn.), a frequent Trump critic, said the defeat is a consequence of putting people without diplomatic experience in charge of diplomatic ventures.

The embargo is set to expire in October under the 2015 Iran nuclear deal. Tim O'Donnell

Belarus' embattled President Alexander Lukashenko on Saturday appealed to his long-time ally Russian President Vladimir Putin as protesters continue to call for his resignation following his recent disputed election victory, which the opposition alleges he rigged.

Lukashenko has been in power for 26 years, but the so-called "last dictator in Europe" is facing one of his strongest challenges yet, as tens of thousands of people remain in the streets, CEOs in the country's up-and-coming information technology sector threaten to leave, and even some riot police put down their shields and embrace demonstrators.

He said it is necessary to contact Putin because the protests are "not a threat to just Belarus anymore." The appeal comes at a rare point of uncertainty in the two countries' relationship, Reuters notes. Lukashenko has recently balked at deepening economic and political ties with Moscow, fearing a breach of Minsk's sovereignty. Russia, in turn, had scaled back subsidies propping up Lukashenko's government, but it seems Putin and Lukashenko are on the same page when it comes to the demonstrations.

Meanwhile, the opposition is re-emerging after Lukashenko cracked down on potential challengers, including Svetlana Tikhanovskaya, who ran against him in last week's election. Tikhanovskaya left the country for Lithuania this week for safety reasons, but resurfaced on social media Friday and said she is ready to enter talks with Lukashenko, mediated by international partners. Read more at Reuters and NPR. Tim O'Donnell