WASHINGTON — Sexual assault in the military has plagued the Pentagon in recent years as a series of high-profile cases, and new data, revealed the extent of the problem. In response, President Obama and members of Congress demanded that military officials more aggressively address the threat and its causes.

Yet few military experts went as far as Donald J. Trump did Wednesday, when he suggested that the integration of women into the armed forces was an underlying cause of sexual assault.

Speaking at a candidates’ forum, Mr. Trump defended one of his Twitter posts from 2013 concerning the high number of sexual assaults in the military, and said that he had been “absolutely correct” in posting a message that said, “What did these geniuses expect when they put men & women together?”

The remarks drew criticism on Thursday from lawmakers and military experts, who said Mr. Trump had displayed ignorance of the Pentagon’s decades-long struggle to curb such assaults and the military justice system that is in place to prosecute them.