While a prime mentor of Johnson, Russell and the then-president Johnson also disagreed over civil rights. Russell, a segregationist, had repeatedly blocked and defeated civil rights legislation via use of the filibuster, and had co-authored the Southern Manifesto in opposition to civil rights. He had not supported the States Rights' Democratic Party of Strom Thurmond in 1948, but he opposed civil rights laws as unconstitutional and unwise. Unlike Theodore Bilbo, "Cotton Ed" Smith and James Eastland, who had reputations as ruthless, tough-talking, heavy-handed race baiters, he never justified hatred or acts of violence to defend segregation. But he strongly defended white supremacy and apparently did not question it or ever apologize for his segregationist views, votes and speeches. Russell was key, for decades, in blocking meaningful civil rights legislation intended to protect African-Americans from lynching, disenfranchisement, and disparate treatment under the law. After Johnson signed the Civil Rights Act of 1964, Russell (along with more than a dozen other southern Senators, including Herman Talmadge and Russell Long) boycotted the 1964 Democratic National Convention in Atlantic City.