I tend to find the objection that having women in combat positions is a case of social engineering somewhat short-sighted. The military has long been a testing ground for social engineering. In the 1st century B.C. the Marian reforms helped transform the Roman legions from being the Roman nation at arms to a professional fighting force. It is a defensible position that those reforms were a major catalyst for the emergence of strongmen such as Sulla and Caesar, as professional soldiers looked to their generals to safeguard their rights, rather than the citizen soldiers who were safeguarding their nation and property. The issue then is not social engineering, but the shape and consequences of that engineering.
Women will now officially be in combat roles. My understanding is that over the past generation they have already been de facto in the “line of fire.” Conservatives, who are skeptical of change, have then to confront a very radical overturning of tradition. The likelihood of this being reversed is low. But, there are different trajectories that this policy could take. It seems that the primary issue that conservatives need to stand on is the fact that proportionality and ‘gender norming’ will not be guiding principles. There seems broad public acceptance of the idea that individual women who have the capacity to serve in combat roles should be given that liberty, but there is no consensus that women should be equally represented in all arms of the military in direct proportion to their overall representation (15 percent).
It is notable to me that The New York Times, an organ of mainstream cultural liberalism, published a cautionary piece on women in combat in Israel, Looking to Israel for Clues on Women in Combat. Even after decades of having women in military roles there has not been an elimination of deep structural differences in males and females in terms of their typical roles. Why? Because males and females differ in bio-behavioral dispositions, and social and cultural mores may not be able to eliminate those differences (often, cultural changes only shift the differences in novel configurations).
Social conservatives who oppose these changes on principle will not be able to turn back the clock in the near term. The best case solution then is an alliance with libertarians who will be able to agree that the fitness of a soldier must be evaluated on an objective and universal set of individual criteria. If sex is no longer to be a bar on general service in combat, nor should it be a category which one uses to alter the rules of evaluation for fitness in that service.