Joe Sestak on the issues, in under 500 words

Key facts about Joe Sestak:

• Current position: N/A
• Age: 67
• Born: Secane, Pennsylvania
• Undergraduate: U.S. Naval Academy
• Date candidacy announced: June 23, 2019
• Previous roles: 3-star admiral in the U.S. Navy, Pennsylvania congressman

Joe Sestak's stance on key issues:

• Climate change: Wants to rejoin the Paris Accord and impose a fee on carbon polluters.
• Health care: Aims to restore the Affordable Care Act and employ a public option to expand access to health insurance. He's also in favor of allowing the re-importation of lower-cost prescription drugs from Canada.
• Education: Supports Common Core and expanding access to early childhood education to all 4-year-olds. He is also seeking to restructure federal student loans.
• Foreign policy: Wants to rejoin the Iran nuclear deal and grow military cyber capabilities.
• Immigration: Ending child separation at the border, passing comprehensive immigration reform, creating a path to naturalization for undocumented immigrants and securing the border with technology such as drones and sensors.
• Women's rights: Supports closing the gender pay gap and guaranteeing a woman's access to reproductive health services.
• Corporate power: Seeks to strengthen antitrust laws and curtail the influence of lobbying. He also wants to enact data privacy reform to ensure "personal data belongs to a person, not to a corporation or government," per his campaign website.

Key criticism of Joe Sestak:

• Sestak is largely seen as having entered the race too late to generate momentum.

1 fun thing about Joe Sestak:

• He walked 422 miles across Pennsylvania to speak with voters during his second bid for Senate, per Washington Post reports.

Go deeper: Everything you need to know about the 2020 candidates

• "After nearly a month of stonewalling, it appears clear that the President has chosen the path of defiance, obstruction, and cover-up," the letter reads.

The state of play: Several White House officials have told Axios' Alayna Treene that the administration has no plans of complying with the committees' demands for interviews or documents without a full House vote formally approving an impeachment inquiry.

The big picture: The Trump administration's initial refusal to turn over the whistleblower complaint on the president's interactions with Ukraine is what led House Speaker Nancy Pelosi to finally support a formal impeachment inquiry.

Go deeper: Trump letter dares Pelosi to hold vote on impeachment inquiry

• Johnson asked the Justice Department earlier this week to look into links between Ukraine and Hillary Clinton's 2016 presidential campaign. His letter questioned the narrative that Biden's actions in Ukraine had nothing to do with his son's connection.
• However, it was also discovered that he signed onto a 2016 letter that mirrored Biden's work to reform Ukraine's prosecutor general and judiciary.
• There is no evidence that Biden's reform work in Ukraine was to protect his son's business dealings, as the president and some of his allies allege, or that he committed any form of corruption.

The state of play: Sondland, a Trump political appointee who donated $1 million to the president's inaugural committee, denied that there was a quid pro quo between the Trump administration and Ukraine's government in a series of text messages that former Ukraine special envoy Kurt Volker provided to a group of House committees investigating the Trump-Ukraine matter.

• "I think it’s crazy to withhold security assistance for help with a political campaign," Bill Taylor, the top U.S. diplomat to Ukraine, texted Sondland.
• Sondland texted back: "Bill, I believe you are incorrect about President Trump's intentions. The President has been crystal clear no quid pro quo's of any kind."
• The New York Times reported that Sondland's response came only after he spoke to the president.

Go deeper: House committees release texts from former Ukraine envoy Kurt Volker