President Trump’s order banning many transgender people from serving has eroded the military’s ability to fight and win wars by narrowing its recruiting pool and lowering morale among transgender troops exempt from the policy, former top military physicians said in a study. Defense Department regulations implemented April 12, 2019, prohibit anyone with gender dysphoria from enlisting but allow transgender service members who were serving before then to remain in uniform. Trump and military officials have argued that barring transgender people from serving would improve readiness and strengthen unit cohesion. But a study published by the Palm Center, a research institute that studies LGBTQ personnel issues in the military, said the opposite has occurred.