President Trump's personal attorney Rudy Giuliani said Tuesday he is refusing to comply with a subpoena from Congress.

Giuliani, who was subpoenaed for documents related to his communications with Ukraine as part of the House's impeachment inquiry, told ABC News he won't provide them.

"If they enforce it then we will see what happens," Giuliani said of the subpoena. He also revealed to ABC News that he is no longer being represented by attorney Jon Sale, whose hiring he announced two weeks ago. Sale told BuzzFeed News' Zoe Tillman he was always planning to only help Giuliani respond to this subpoena.

Tuesday was the deadline for Giuliani to comply with the subpoena. In a letter late last month, House Intelligence Committee Chair Adam Schiff (D-Calif.), House Foreign Affairs Committee Chair Eliot Engel (D-N.Y.), and House Oversight Committee Chair Elijah Cummings (D-Md.) cited the whistleblower complaint alleging Trump abused his power in an attempt to get Ukraine to investigate former Vice President Joe Biden, as well as Giuliani having admitted he asked Ukraine to do so.

"I consider their inquiry to be a joke," Giuliani told The New York Daily News Tuesday, calling it an "an abomination of due process."

Sale in a letter to Congress says Giuliani "will not participate because this appears to be an unconstitutional, baseless, and illegitimate 'impeachment inquiry'" and because the subpoena is "overbroad, unduly burdensome" and seeks documents that are "protected by attorney-client, attorney work-product, and executive privileges."

CNN reports people close to Giuliani have been urging him to hire a criminal lawyer, but Giuliani, in reference to no longer being represented by Sale, told the Daily News it's "silly to have a lawyer when I don't need one." Brendan Morrow

Former Vice President Joe Biden may have emerged as the leading Democratic presidential candidate because the party's more moderate bloc rallied around him, but now that the nomination looks likelier than ever, his campaign is making sure they don't lose support from the progressive wing come November, Politico reports.

"The dirty little secret is everyone's talking to Biden's campaign," said Sean McElwee, co-founder of liberal think tank Data for Progress. "There will be fights, but at the end of the day, progressives still hold votes in the Senate and increasingly Democratic voters stand behind our views. I expect we'll see Biden embracing key planks of the ambitious agenda progressives have outlined on issues like climate and pharmaceutical policy."

Most of Biden's support comes from older voters, so his team is trying to court younger generations who are more likely to back the policies MccElwee referred to. They're reaching out to groups like the climate-focused Sunrise Movement, as well as other organizations tied to gun control, immigration, and other issues. Most groups are committed to backing whoever the nominee is against Trump, but there is a sense that a lack of turnout among younger, progressive voters could hinder Biden if he's the nominee, making these efforts more crucial. And he may need to meet some expectations to convince people.

Evan Weber, the national political director for the Sunrise Movement, said their explicit support for Biden — compared to a broad anti-Trump campaign — depends on whether his campaign can "demonstrate that they are taking the climate crisis seriously." Read more at Politico. Tim O'Donnell

The U.S. government has begun to use cellphone data to get a better sense of people's movement in up to as many as 500 cities amid the novel coronavirus pandemic, The Wall Street Journal reports.

The tactic is not meant to track individuals, and names aren't included in the data, but instead is geared toward figuring out where people might be congregating in large numbers as calls for social distancing and lockdowns become the norm across the country. In doing so, the Centers for Disease Control and Prevention, in conjunction with state and local officials, hope to get an idea of how the coronavirus might be spreading so they can further curb its advance.

The data, which is coming from the less-regulated mobile advertising industry rather than cell phone carriers, could also provide information on whether people are complying with their area's shelter-in-place or stay-at-home orders.

Despite the intentions of the efforts, such projects will undoubtedly raise concerns about government invasion of privacy, and, while even some privacy activists understand the necessity of such efforts, they want stronger safeguards in place. Read more at The Wall Street Journal and read more about coronavirus surveillance here at The Week. Tim O'Donnell

Former Oklahoma Sen. Tom Coburn (R) died Saturday at his home in Tulsa after a long battle with prostate cancer. He was 72.

Coburn had battled health issues for many years, and his bout with cancer led him to retire from the Senate in 2015, two years before his second term was up.

An obstetrician by training, Coburn — who served in the House before winning a seat in the upper chamber — was known for his fierce commitment to conservatism, both fiscally and socially. He was opposed to the expansion of the federal government, abortion rights, and same-sex marriage, and did not believe in global warming science.

Still, the senator also was hailed for bipartisanship — he teamed up with former Sen. Carl Levin (D-Mich.) to issue a report on the 2008 financial crisis which accused Goldman Sachs and other powerful institutions of deception and greed. The Washington Post notes he gained the respect of many Democrats for his role in inquiries into corruption, tax avoidance, and fraudulent social security claims.

Levin said Coburn was a "terrific oversight partner in the Senate" thanks to the fact that he was "more interested in facts than politics." Read more at The Washington Post. Tim O'Donnell

While children certainly aren't immune to the dangers of the novel COVID-19 coronavirus, studies show they are at substantially lower risk of developing severe symptoms than adults.

That's rare when it comes to infectious diseases. Nicholas Christakis, a physician and professor of social and natural science at Yale University, points out that such diseases are the leading killers of children under the age of 5 around the globe each year. Yet, COVID-19 does not appear to be a contributor to the trend.

Christakis says scientists aren't sure exactly, but there are some theories developing. One possibility is that kids have more "adaptive" immune systems because they're still developing. Immune systems for adults are based more on memory, making them more susceptible to an unfamiliar virus, like the new coronavirus behind the pandemic. Along those lines, because many adults have built up immunity to other coronaviruses, their bodies might be overreacting to the virus.

Another dose of good news, Christakis surmises, is that children probably won't become more susceptible to severe cases of COVID-19 if it becomes endemic as they age, even if they lose some of the theoretical immunological protections that are present only in youthful systems. Tim O'Donnell

Journalists from three of the United States' most prestigious publications may not be able to report from China anymore, but Taiwan is offering them refuge.

Taiwan's Foreign Minister Joseph We invited American journalists from The New York Times, The Wall Street Journal, and The Washington Post, to set up shop on the China-claimed island after the newspapers were stripped of their credentials by Beijing. Wu said reporters from the prestigious U.S. publications would be welcomed with "open arms and lots of genuine smiles."

There reportedly aren't many permanent foreign correspondents stationed in Taiwan, and none of the three papers have a full-time presence on the island, so it remains to be seen if they'll take up the offer.

China announced earlier this month that it was revoking the papers' accreditations in their China bureaus, as well as preventing them from operating in Hong Kong. Beijing said the decision was retaliation for Washington labeling Chinese state media as diplomatic missions.

Taiwan has received praise for its handling of the novel coronavirus pandemic in part because the island has stepped up its border controls, mostly allowing entry only to permanent residences. But it seems they'd make an exception in this case. Read more at The Hill and Reuters. Tim O'Donnell

The novel coronavirus pandemic has shown that governments have the ability to do a lot more with their financial resources, said Michael Marmot, a professor of epidemiology and public health at the University College London, per The Guardian.

Marmot, who is also the chair of the commission of the social determinants of health at the World Health Organization, told reporters at a virtual meeting organized by Plan B and Extinction Rebellion, that "with COVID-19 everything went out the window" and that it turns out lack of government spending in the past was a choice (and not a good one, he argues), rather than a necessity. "The government can spend anything," he said, referring specifically to the United Kingdom in this instance.

Marmot said the pandemic has shown how swiftly governments can respond, but his hope is that such action continues going forward, which he argues has not been the case for other long-term crises like climate change. "Coronavirus exposes that we can do things differently," he said. "We must not go back to the status quo ante."

David King, who served as the U.K.'s chief scientific adviser between 2000 and 2008, agreed, calling for governments to address similar recovery plans to restructure the global economy, so it better fits a fossil fuel-free world. Read more at The Guardian. Tim O'Donnell