The university filed its lawsuit in conjunction with 12 others (Courtesy Creative Commons)

Dozens of Roman Catholic schools, institutions and diocese sued the administration in a coordinated filing, ABC reported. This is the largest push-back against the controversial mandate thus far. 

According to TPM:

The issue was the subject of a heated firestorm earlier this year. The administration tweaked its rule to accommodate religious nonprofits like Catholic universities and hospitals. Churches are exempt. Republicans continued to demand that Obama reverse the rule entirely but backed down after receiving immense blowback.

"We do not seek to impose our religious beliefs on others," Notre Dame's president, the Rev. John Jenkins said. "We simply ask that the government not impose its values on the university when those values conflict with our religious teachings."

From the Huffington Post:

Other religious colleges and institutions have already filed federal suit over the mandate, but observers had been closely watching for Notre Dame's next step.

The university, among the best-known Catholic schools in the country, has indicated past willingness to work with President Barack Obama, despite their differences with him on abortion and other issues. Notre Dame came under unprecedented criticism from U.S. bishops and others in 2009 for inviting Obama, who supports abortion rights, as commencement speaker and presenting him with an honorary law degree.

The Franciscan University of Steubenville announced last week that it was discontinuing its health insurance plan because of the mandate.