Donald Trump has mishandled sensitive information with such frequency that I was able to put together a top-10 list a couple of weeks ago. I didn’t expect the collection to grow quite so quickly, but yesterday’s impeachment hearing offered another striking example of the phenomenon.

William Taylor, the top U.S. diplomat in Ukraine, told lawmakers about a July telephone call between the president and Ambassador to the E.U. Gordon Sondland – a table in a Ukrainian restaurant – in which Trump sought information on Ukraine helping target the president’s domestic political opponents. It was a significant development, further linking Trump to the broader scandal.

But as the Washington Post noted, there was a related problem:

“The security ramifications are insane – using an open cellphone to communicate with the president of the United States,” said Larry Pfeiffer, a former senior director of the White House Situation Room and a former chief of staff to the CIA director. “In a country that is so wired with Russian intelligence, you can almost take it to the bank that the Russians were listening in on the call.” […] Russia already has shown its ability to monitor U.S. diplomats’ calls in Kyiv, and the Kremlin has no hesitation in leaking them when it suits its interests.

The Post also spoke to a former senior U.S. intelligence official who explained that calling a president from a cellphone violates protocols set up to protect senior administration officials’ communications. “It’s indicative of a lack of concern for operational security,” he said.

Michael McFaul, the former U.S. Ambassador to Russia, added that the “whole world was listening in” to the Trump/Sondland conversation because it was held on a cellphone.

Of course, given the legal and political implications, if other countries did hear the call, it meant other countries learned about the American president’s scheme to extort Ukraine, creating possible blackmail opportunities against the White House.

And with that in mind, it’s probably a good time to update my entirely subjective rundown of the most egregious examples of Trump mishandling sensitive information.

10. In May 2017, Trump had a chat with Philippine President Rodrigo Duterte in which the Republican shared information about dispatching two nuclear submarines off the coast of the Korean peninsula. By one account, Pentagon officials were “in shock” over Trump’s willingness to share such information. “We never talk about subs!” three officials told BuzzFeed News, referring to the military’s belief that keeping submarines’ movements secret is key to their mission.

9. Trump has refused to give up his unsecured smart phones, which creates additional security risks.

8. On a related note, given the security, political, and diplomatic implications, the aforementioned Trump/Sondland call deserves a spot on this list.

7. In September 2019, during a photo-op at an event along the U.S./Mexico border, the president seemed eager to boast to reporters about detailed technological advancements in border security. It fell to Lt. Gen. Todd Semonite, the acting head of the Army Corps, to interject, “Sir, there could be some merit in not discussing that.”

6. In February 2018, Trump ignored the pleas of many U.S. officials and recklessly declassified information from the so-called “Nunes Memo” in the hopes of advancing a partisan scheme.

5. In February 2017, Trump discussed sensitive details about North Korea’s ballistic missile tests with the prime minister of Japan at a Mar-a-Lago dining area, in view of wealthy civilians/customers.

4. In early October 2019, Trump publicly discussed American nuclear weapons in Turkey, something U.S. officials have traditionally avoided disclosing and/or confirming.

3. In August 2019, Trump published a tweet about a failed Iranian launch, which included a detailed photo. As MSNBC’s Andrea Mitchell reported, it wasn’t long before observers expressed concern about Trump possibly releasing classified material.

2. Two weeks ago, Trump needlessly blurted out all kinds of tactical and operational details about the al-Baghdadi mission.

1. Just four months into Trump’s presidency, he welcomed Russian Foreign Minister Sergei Lavrov and Russian Ambassador to the U.S. Sergei Kislyak into the Oval Office – at the request of Russian President Vladimir Putin – for a visit that was never fully explained.

It was in this meeting that Trump revealed highly classified information to his Russian guests for no apparent reason. The Washington Post reported at the time, “The information the president relayed had been provided by a U.S. partner through an intelligence-sharing arrangement considered so sensitive that details have been withheld from allies and tightly restricted even within the U.S. government, officials said.”

The Wall Street Journal added, “According to one U.S. official, the information shared was highly sensitive and difficult to acquire and was considered extraordinarily valuable.”

This list, incidentally, is not comprehensive. There are other examples.

At this point, I imagine some of the president’s detractors might suggest curtailing his access to intelligence briefings, but that’s probably an unnecessary call: by all accounts, Trump often skips his intelligence briefings anyway.

Postscript: Remember when the political world told the American electorate that Hillary Clinton’s information security issues were the single most important issue in the 2016 election cycle? Now seems like a good time for some of the folks who peddled that line to revisit their earlier efforts and assumptions.