No doubt Senator Eugene McCarthy was an unabashed liberal on many issues. And it's very likely that he, at a minimum, questioned Senator Joe McCarthy's anti-Communist crusade. But, as a senator, he most certainly didn't "take on Sen. Joseph McCarthy."
According to the Biographical Directory of the United States Congress, Eugene McCarthy was elected to the U.S. Senate in 1958. This was a year after Senator Joseph McCarthy had died.
The Tribune article also takes note of the widely reported fact that in 1968 Senator Eugene McCarthy won 42 percent of the New Hampshire primary vote against President Lyndon Johnson: "Johnson, despite his incumbent's grip, could score only 49 percent."
What often goes unmentioned is that Johnson had declined to have his name on New Hampshire's presidential preference ballot. Thus, his votes all were write-ins. Getting almost half the votes via write-in ballots was a notable achievement, even for an incumbent president.