There have been many rogues and rascals who have haunted the Senate chambers in the past 200-plus years. Senator Theodore Gilmore Bilbo is a worthy candidate for your consideration as "The Worst US Senator In History".
Theodore Gilmore Bilbo (October 13, 1877 – August 21, 1947) twice served as governor of Mississippi (1916–20, 1928–32) and later was elected a U.S. Senator (1935–47). A lifelong Democrat, he was a filibusterer whose name was synonymous with white supremacy—like many Southern Democrats of his era, Bilbo believed that black people were inferior; he defended segregation, and was a member of the Ku Klux Klan.
The five foot two inch Bilbo was also well-known for his frequent practice of illeism, the use of the third person to refer to oneself.
In the YouTube video below, Jack Webb, later of Dragnet fame, in his 1946 radio program paints a damning audio portrait of then Senator Bilbo. Perhaps to avoid potential lawsuits or perhaps merely sarcastically, Webb repeatedly tells his audience, "Theodore Gilmore Bilbo is an honorable man and we don't intend to prove otherwise" as proved otherwise.
The following quotes illustrate what sort of person he was. His 1945 quotation starting with "There are five million Jews in the United States and the majority of them are fine public citizens..." might sound familiar. A current political figure a few years ago said of a certain nationality, "...They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."
Theodore G. Bilbo, 1938:
"When once the flat-nosed Ethiopian, like the camel, gets his proboscis under the tent, he will overthrow the established order of our Saxon civilization." --In reference to NAACP head Walter White.
"If you succeed in the passage of this bill, you will open the floodgates of hell in the South. Raping, mobbing, lynching, race riots, and crime will be increased a thousandfold; and upon your garments and the garments of those who are responsible for the passage of the measure will be the blood of the raped and outraged daughters of Dixie, as well as the blood of the perpetrators of these crimes that the red-blooded Anglo-Saxon white Southern men will not tolerate...It is essential to the perpetuation of our Anglo-Saxon civilization that white supremacy be maintained, and to maintain our civilization there is only one solution, and that is either by segregation within the United States or by deportation of the entire Negro race to its native heath, Africa." --In a speech opposing a Senate anti-lynching bill
"It is the height of folly to assume that environment, discipline, education, and all other external devices can affect the blood, smooth down inequalities between individuals of the same breed, much less between different breeds, or transmute racial qualities. The Germans appreciate the importance of race values. They understand that racial improvement is the greatest asset that any country can have...They know, as few other nations have realized, that the impoverishment of race values contributes more to the impairment and destruction of a civilization than any other agency." --In a May 24 speech proposing legislation to return US blacks to Africa
Theodore G. Bilbo, 1939:
"It is further a plan of the almighty that the Negroes may be transferred back to the land of their forefathers." --In a speech on the Senate floor in April
Theodore G. Bilbo, 1944:
"When this war is over and more than two million Negro soldiers, whose minds have been filled and poisoned with political and social equality stuff, return and ‘hell breaks out’ all over the country, I think I’ll get more help in settling the Negroes in Africa." --In a speech to the Mississippi State legislature on March 22
Theodore G. Bilbo, 1945:
"There are five million Jews in the United States and the majority of them are fine public citizens, but if Jews of your type don’t quit sponsoring and fraternizing with the Negro race you are going to arouse so much opposition that they will get a very strong invitation to pack up and resettle in Palestine, the homeland of the Jews, just as we propose to provide for the voluntary resettlement of the American Negro in West Africa their fatherland. Now do not pop-off and say I am in favor of sending the Jews to Palestine. What I am trying to say to you is that there are just a few of you New York ‘kikes’ that are fraternizing and socializing with the Negroes for selfish and political reasons and if you keep it up you will arouse the opposition of the better class of your race." --To Leonard Golditch, executive secretary of the National Committee to Combat Anti-Semitism
Theodore G. Bilbo, 1946:
"I am ready to wage the most strenuous fight of my life to defeat the Fair Employment Practices Commission, the anti-poll tax bill, the anti-lynching bill, and the $4 billion loan to England...If you draft Negro boys into the army, give them three good meals a day, a good uniform and let them shoot craps and drink liquor around the barracks for a year, they won’t be worth a tinker’s damn thereafter." --In an announcement that he would seek re-election that year
"I call on every red-blooded white man to use any means to keep the niggers away from the polls[;] if you don’t understand what that means you are just plain dumb. I’m calling on every red-blooded American who believes in the superiority and integrity of the white race to get out and see that no nigger votes...and the best time to do that is the night before!" --In a speech to his white supporters during his successful re-election campaign in June of that year
"No man can leave the Klan. He takes an oath not to do that. Once a Ku Klux, always a Ku Klux." --On the radio program "Meet the Press." --"I deny that I exhorted, agitated, and made any inflammatory appeals to the passions and prejudices of the white population to foster, stimulate, inspire, create and intensify a state of acute and aggravated tension between the white and Negro races in the state of Mississippi... I want to say right here off the record that the Negroes of Mississippi have never had a better friend." --United States Senate, 79th Congress, 2nd session, Hearings Before the Special Committee to Investigate Senatorial Campaign Expenditures" --Take Your Choice, Separation or Mongrelization
"The principle of segregation of the White and Negro races in the South is so well known that it requires no definition. Briefly and plainly stated, the object of this policy is to prevent the two races from meeting on terms of social equality. By established practice, each race maintains its own institutions and promotes its own social life." --Chapter Four: Southern Segregation and the Color Line.
"What is the real issue at stake? Why this determination on the part of the South to maintain the color line and to fight back with all her strength against the combined efforts of certain groups in our Nation, white and black, to break down segregation and to destroy Southern ideals and customs? The answer is simple. The South stands for blood, for the preservation of the blood of the white race. To preserve her blood, the white South must absolutely deny social equality to the Negro regardless of what his individual accomplishments might be. This is the premise - openly and frankly stated - upon which Southern policy is based. This position is so thoroughly justified in the minds of white Southerners that it is sometimes difficult for them to comprehend the reasoning of those who seriously dispute it." --Chapter Four: Southern Segregation and the Color Line.
"If we sit with Negroes at our tables, if we attend social functions with them as our social equals, if we disregard segregation in all other relations, is it then possible that we maintain it fixedly in the marriage of the South's Saxon sons and daughters? The answer must be "No." --By the absolute denial of social equality to the Negro, the barriers between the races are firm and strong. But if the middle wall of the social partition should be broken down, then the mingling of the tides of life would surely begin. It would be a slow process, but the result would be the same. And though the process be gradual, it would be none the less irresistible and inevitable. The lower strata of the white population would probably feel the first effects, and within the foreseeable future the middle and upper classes would be invaded. Then, the Southern White race, the Southern Caucasian, would be irretrievably doomed." --Chapter Four: Southern Segregation and the Color Line