Joined by Wisconsin Democrat Tammy Baldwin, McCaskill called the current legal landscape a "complex labyrinth between different rules, different standards of proof, different, state statues."
"We can't even agree on the definition of consent," she said.
McCaskill said she was working with fellow Democrats Kirsten Gillibrand of New York and Richard Blumenthal of Connecticut on drafting legislation that she expects will get a first look shortly after the third roundtable discussion, set for a month from now.
Monday's hearing focused on two of the laws that dictate how schools are to handle campus assault: the Clery Act, which requires institutions to disclose crime statistics, and the Campus SaVE Act, which was made law as part of the 2013 renewal of the Violence Against Women Act that requires Clery reporting data to include statistics on domestic violence, dating violence and stalking.
Participants in the discussion, which included a victim of campus assault, a Department of Education official, a university compliance officer and a university police chief, called for clarification in the tangle of competing laws that have left universities unsure of when they were required to report data and what their responsibilities were in responding to reports of assaults.
As is, McCaskill said, the law encourages institutions to treat sexual assault requirements as a "box to check."
"Nothing is more frustrating than a rote exercise that you're required to do that has no meaning," she said.
McCaskill said the upcoming legislation would likely focus on changing how universities are penalized when they are found to be in violation of the Clery Act regulations or Title IX regulations, a gender discrimination law that is frequently cited by victims of sexual assault in instances where schools failed to protect students or to respond adequately in the event of an assault.
The current penalty for violation is complete withdrawal of federal student aid funding, something McCaskill said would unfairly punish students who had nothing to do with the university's failure to comply. Instead, she said the group was considering changing the penalty to a portion of federal aid, or a fine adjusted based on the university's student population, endowment or other measure.
New legislation would likely also tackle how to balance victim autonomy -- the assault survivor's right to retain her privacy or refuse to pursue prosecution against her alleged assailant -- and the need to act based on the interest of public safety.
In a 2002 study, David Lisak of the University of Massachusetts-Boston found some 63 percent of rapists were repeat offenders, with an average of 5.8 rapes per assailant. And a National Institute of Justice study estimated between 20 and 25 percent of women at higher educational institutions are the victims of completed or attempted rape, but less than 5 percent of those assaults were reported to law enforcement.