Potential Democratic presidential candidate Sen. Kamala Harris, D-Calif., hasn't responded to an invitation to plunge into a pool of ice water to raise money for the D.C. Special Olympics in February.

She was publicly invited to attend last week by the Knights of Columbus, a Catholic charity group she recently criticized as extreme. The 136-year-old group invited Harris and Sen. Mazie Hirono, D-Hawaii, to participate in the popular D.C. fundraiser after the senators described the organization earlier this month as having “extreme positions” and having “opposed a woman’s right to choose."

In a Dec. 22 letter to the senators, the Knights of Columbus’s Capitol Hill chapter defended the organization and extended an invitation for Harris and Hirono to get involved in its charitable activities.

"We recently read about statements which expressed the fear that the Knights of Columbus held many extreme beliefs. It is our great pleasure to assure you that this fear is not grounded in any truth. The Knights of Columbus in general, and O’Boyle Council in particular are dedicated to the three fundamental principles of charity, unity, and fraternity," wrote the Knights of Columbus Capitol Hill council.

“We wish to formally invite you all to join us for any social or charitable event,” the group continued. “In fact, this February we are doing the Polar Plunge to raise funds for DC Special Olympics. You and anyone you know are more than welcome to join us either jumping in the cold water or sponsoring our team.”

Spokespersons for Harris and Hirono did not respond to questions about whether the senators would participate in the fundraiser, which entails jumping into a freezing above-ground pool near the southeast waterfront in D.C. on Feb. 2.

The Knights of Columbus said it has not heard back from the senators after reaching out to them electronically last week and hand-delivering another invitation Thursday.

“So far we have not heard a response back from either Senator or their staff,” said Knights of Columbus Patrick Cardinal O'Boyle Council 11302 Financial Secretary Patrick Abbott.

The Knights of Columbus came under fire from Harris and Hirono in questions they sent to federal court judicial nominee Brian Buescher in early December. Hirono claimed the organization, which Buescher has belonged to since he was 18, “has taken a number of extreme positions,” such as opposing gay marriage in 2008.

Harris quizzed Buescher on whether he agreed with Knight’s of Columbus’s leader’s opposition to abortion and asked if Buescher was “aware that the Knights of Columbus opposed a woman’s right to choose when you joined the organization?”

Buescher replied that he did “not recall if I was aware whether the Knights of Columbus had taken a position on the abortion issue when I joined at the age of 18.” He also said the group “is a Roman Catholic service organization with approximately two million members worldwide. The organization has a religious and charitable purpose.”

The Polar Plunge is a popular annual charity event that brings together D.C. residents, politcos, athletes, and media figures to raise money for the Special Olympics.

The event will take place on Feb. 2 at The Yards Park. Participants this year and in years past include Special Olympics Chairman and Kennedy scion Tim Schriver, D.C. United soccer player Steve Birnbaum, former Bush-Cheney spokesman Dan Ronayne, and Fox 5 weather anchor Tucker Barnes.

Music will be provided by Suspicious Package, a band that includes ex-Bloomberg writer Tim Burger, Washington Post cartoonist Tom Toles, former Politico scribe Josh Meyer, Housing and Urban Development deputy assistant secretary Bryan Greene, and Deputy Assistant U.S. Trade Representative Christina Sevilla.