I followed a rabbit trail from The Bellarmine Report (Robert Sungenis) over to a story entitled,"Pope's foot-wash a final straw for traditionalists." The article states,
The church's liturgical law holds that only men can participate in the rite, given that Jesus' apostles were all male. Priests and bishops have routinely petitioned for exemptions to include women, but the law is clear.
Francis, however, is the church's chief lawmaker, so in theory he can do whatever he wants.
"The pope does not need anybody's permission to make exceptions to how ecclesiastical law relates to him," noted conservative columnist Jimmy Akin in the National Catholic Register. But Akin echoed concerns raised by canon lawyer Edward Peters, an adviser to the Vatican's high court, that Francis was setting a "questionable example" by simply ignoring the church's own rules.
Now, Google search the quote from Jimmy Akin, and notice that a lot of news sites picked it up. The quote in context can be found here. He states,
2. How does Pope Francis's decision relate to this?
Pope Francis's decision goes beyond what is provided in these texts in at least one respect: Instead of washing the feet of adult males, he decided to wash the feet of young women as well.
The fact that one of them was a Muslim does not go beyond what the letter of the text specifies, since it does not indicate that the chosen men are to be Catholics (or other Christians).
One would expect that they would be Catholics, and one could argue that this is implied in the text, but since Pope Francis is now the individual who is ultimately responsible for interpreting the text, if he judges that it does not prevent washing the feet of non-Christians then it doesn't.
His decision does go beyond the text in the matter of men, however.
3. Can Pope Francis just do things that aren't provided for in the law?
Yes. The pope does not need anybody's permission to make exceptions to how ecclesiastical law relates to him. He is canon law's ultimate legislator, interpreter, and executor.
And it's not uncommon, at least in recent decades, for a pope to make exceptions to the law in how papal ceremonies are performed.
John Paul II frequently held liturgies that departed from what the Church's liturgical texts provide, particularly when he was making a form of dramatic outreach, and Pope Francis seems to be following in his footsteps.