President Biden signed an executive order on Monday overturning the Trump administration's ban on transgender Americans serving in the military.

Why it matters: The ban, which allowed the military to bar openly transgender recruits and discharge people for not living as their sex assigned at birth, affected up to 15,000 service members, according to tallies from the National Center for Transgender Equality and Transgender American Veterans Association.

• A 2016 RAND Corporation study estimated that the number of active-duty transgender troops could range from 2,000 to 11,000, but stressed that the true number could vary based on self-reporting.
• "Allowing all qualified Americans to serve their country in uniform is better for the military and better for the country because an inclusive force is a more effective force," the White House said in a statement. "Simply put, it’s the right thing to do and is in our national interest."

Where it stands: Biden ordered military records to be corrected if service members were discharged or denied reenlistment or continued service due to their gender identity.

Background: After a decades-long ban, trans people were first able to serve openly again in the armed forces in June 2016, under President Obama.

• Multiple legal battles ensued after President Trump first tweeted in July 2017 that transgender people would not be allowed "to serve in any capacity in the U.S. Military," citing medical costs and "disruption."
• The Supreme Court let the ban proceed in a 5-4 vote in January 2019, after two federal judges had temporarily blocked it following a lawsuit from the ACLU.

What they're saying: LGBTQ and legal advocates praised the policy reversal, which comes after Democrats in the 2020 race held one of the most prominent political discussions of trans rights to date.

• But advocates are also looking for the administration to do more for LGBTQ rights after the Trump administration worked to undo major gains secured under President Obama.
• One of Biden's "day one" executive orders bolstered last year's Supreme Court ruling that LGBTQ employees cannot be fired based on gender identity or sexual orientation, and charged federal agencies with changing old policies if they allow for such discrimination.

"Repealing the military ban sends a powerful message that transgender people belong in our country," ACLU senior legislative representative Ian Thompson said in an emailed statement.

• The ACLU hopes that Biden's reversal of the ban "is the first of many essential steps to not only roll back the many discriminatory policies from the Trump administration but go further than any previous administration in fully recognizing transgender and non-binary people," Thompson said.
• Gillian Branstetter, a spokesperson for the National Women’s Law Center, said she is optimistic that the Biden administration will keep LGBTQ rights a priority while juggling the pandemic and other crises — partially due to key nominations like Vanita Gupta as associate attorney general and Xavier Becerra as Health and Human Services secretary.