"We will use this additional time to evaluate more carefully the impact of such accessions on readiness and lethality," Mattis wrote in a memo that was obtained by the Associated Press.
This is only a false excuse to prevent trans people from joining the US military.
The Obama administration had done many studies. Ashton Carter, who was secretary of defense under the Obama administration, had announced that the Pentagon would take a year to find how to begin welcoming transgender recruits. This review period ended this year.
"The Department of Defense spent over a year intensively studying the integration of transgender people in the military before allowing them to serve openly in June 2016, and it’s had over a year since then to observe the results — namely, that allowing transgender people to serve without fear or lying about who they are is good for military readiness and good for morale," Mara Keisling, executive director of the National Center for Transgender Equality, wrote in a statement.
"The evidence is already clear: even though thousands of transgender people are already serving openly in the military, the hypothetical problems and concerns some had speculated about have simply not materialized. The military needs to be able to recruit people based on their skills and abilities, regardless of whether they’re transgender. Impeding that by prolonging the blanket ban on new transgender service members who are fit and ready to serve is bad policy. This last-minute decision to reverse the Department of Defense’s carefully considered plan is harmful, it’s not supported by the facts, and it risks telling the thousands of transgender people who are already serving their country — and the thousands more who have waited for years to join their ranks — that their service and their sacrifice is not wanted and not valued."
I don't think we will see a policy change from that administration in six months.
It should be noted that the new defense secretary, James Mattis, is not only opposed to LGBTQ troops but also to military women.