The four-paragraph letter, addressed to Senate Judiciary Chairman Chuck Grassley , R- Iowa , and ranking Democrat Sen. Dianne Feinstein , represented a stunning turn of events. The ABA had bestowed its highest rating of unanimous, "well-qualified" for the Supreme Court, and Kavanaugh pointed to the ABA's support during Thursday's proceedings.

In a Thursday night letter that followed an emotional and compelling day of hearings at which Kavanaugh again denied the nearly four-decades-old allegations of Dr. Christine Blasey Ford , one of three named accusers, the ABA sided with Senate Democrats out of its "respect for the rule of law and due process under law."

The American Bar Association has asked the Senate Judiciary Committee to suspend its consideration of Brett Kavanaugh's nomination to the Supreme Court until an FBI investigation is completed into multiple sexual assault allegations.

Supreme Court nominee Judge Brett Kavanaugh, with his wife Ashley, arrives to testify before the Senate Judiciary Committee on Capitol Hill in Washington, DC,on September 27,2018.

"Each appointment to our nation's Highest Court (as with all others) is simply too important to rush to a vote," ABA President Robert Carlson wrote in the letter. "Deciding to proceed without conducting additional investigation would not only have a lasting impact on the Senate's reputation, but it will also negatively affect the great trust necessary for the American people to have in the Supreme Court."

Senate Republicans, though, have deflected Democrats' call for an FBI probe. A committee vote on Kavanaugh is expected Friday, with a vote on his nomination possible by as early as the weekend.

"For 12 years, everyone who has appeared before me on the D.C. Circuit has praised my judicial temperament," Kavanaugh said Thursday. "That's why I have the unanimous, well-qualified rating from the American Bar Association."

Sen. Lindsey Graham, R-South Carolina, also pointed to the ABA's grading as evidence of Kavanaugh's qualifications on Thursday.

"Here's my understanding, if you lived a good life, people will recognize it like the American Bar Association has, the gold standard," he said. "His integrity is absolutely unquestioned."

In the closing of his letter, Carlson wrote, "Respectfully, the Senate should recognize that a thorough FBI investigation will demonstrate its commitment to a Supreme Court that is above reproach."

The religious America Magazine also walked back its previous support for Kavanaugh on Thursday, calling for his nomination to be withdrawn "in the best interests of the country."