Former President Jimmy Carter credited Walter F. Mondale, his onetime vice president who died on Monday at 93, with transforming the office from a secondary role to a governing partner with his political skill and personal integrity.
Mr. Carter led the tributes to Mr. Mondale, many of them coming from the political left.
They recalled Mr. Mondale, the 42nd vice president and a former U.S. senator who lost the 1984 presidential election in a landslide to Ronald Reagan, as an indefatigable advocate for liberal causes like civil rights reform and a gracious public servant who selected the first female running mate on a major party ticket, Geraldine Ferraro.
In a statement, Mr. Carter, 96, called Mr. Mondale, whose nickname was Fritz, the best vice president in American history.
“During our administration, Fritz used his political skill and personal integrity to transform the vice presidency into a dynamic, policy-driving force that had never been seen before and still exists today,” Mr. Carter said. “He was an invaluable partner and an able servant of the people of Minnesota, the United States, and the world. Fritz Mondale provided us all with a model for public service and private behavior.”
Vice President Kamala Harris, the first woman elected to the office, lauded Mr. Mondale for his collaborative role in the Carter administration and for his selection of Ms. Ferraro in 1984 as his running mate.
“He brought the president and the vice President closer together, redefining the relationship as a true partnership,” Ms. Harris said in a statement on Monday night. “Vice President Mondale worked side by side with President Carter as the two endeavored to end the arms race, promote human rights and establish peace.”
Ms. Harris said that Mr. Mondale’s choice of Ms. Ferraro had opened “a new door to the future,” to borrow his words.
Senator Amy Klobuchar, a Democrat from Mr. Mondale’s home state of Minnesota who ran unsuccessfully for president last year, said on Twitter that he had been a mentor and friend to her, and that he was kind and dignified until the end.
“On the wall of the Carter Library is a quote of Walter Mondale’s at the end of their time in office,” Ms. Klobuchar said. “ ‘We told the truth. We obeyed the law. We kept the peace.’ That pretty much sums up Walter Mondale’s life and service.”
Senator Dianne Feinstein, Democrat of California, said on Twitter that Mr. Mondale was well-respected and liked on both sides of the aisle.
“This was a man of intelligence and integrity, and he practiced both during his long career in public service as a state attorney general, ambassador, U.S. senator and vice president,” she said.
Senator Tim Kaine of Virginia, the Democratic vice-presidential nominee in 2016, termed Mr. Mondale on Twitter Monday night as a visionary.
“So much to say about Walter Mondale,” Mr. Kaine said. “I will always think of him as the chief sponsor of the Fair Housing Act and first presidential candidate to ask a woman to join him on the ticket. Ahead of his time.”
The tributes to Mr. Mondale did not come exclusively from the left.
Senator Bill Hagerty, Republican of Tennessee, extended his sympathies to Mr. Mondale’s family Monday night on Twitter.
“While Walter Mondale and I had different political beliefs, when I was U.S. Amb. to Japan, a position he once held, he was always gracious and kind with his time & advice,” he said. “I will treasure our calls & correspondence.”
The Rev. Franklin Graham, the leader of Samaritan’s Purse, an evangelical organization, said on Twitter that Mr. Mondale had served the nation faithfully for years and that his family would appreciate the prayers of Americans.