There are about 15,000 transgender people serving in the military, but no one knows how many will be left a few months from now.

On Friday, the Trump administration’s ban barring many transgender people from serving in the military went into effect. President Trump announced the ban in 2017, but it only now goes into place after a series of legal challenges and delays in implementation. Some conservatives are celebrating this development, but they really shouldn’t be — Trump’s transgender ban is unnecessary, antagonistic, and a blot on the president’s otherwise decent record on LGBT rights.