The rest of the Senate! Next, the vice presidency.
The other black Senator was Carol Moseley Braun, who defeated Alan Dixon in the primary in 1992 for Illinois' Senate seat, becoming the first (and so far, only) African-American woman in the Senate, though she was in turn defeated by Peter Fitzgerald, the first Republican to be elected to the Senate from Illinois in 20 years. He retired after that one term, having alienated much of the Republican Party in Illinois, and Barack Obama succeeded him, demolishing Alan Keyes in the general election 81 to 19%. When Obama was elected President in 2008, the governor of Illinois, notoriously corrupt Rod Blagojevich, appointed Roland Burris to that seat, after being arrested for various bribery and corruption charges, including trying to sell that very appointment. Burris, after being held up by the Senate, who doubted his personal integrity (mostly from accepting Blagojevich's offer, and getting it in the first place), did eventually take the seat, probably in part because he was also black, and people felt they would take some heat for blocking the “only black Senator!!!!” Burris is incredibly unpopular, and terrible at fundraising, so he had no chance to win the Senate primary in 2010, and didn't even try. Alexi Giannoulias, IL's State Treasurer fairly narrowly beat David Hoffman, Chicago's Inspector General, and lost very narrowly to Mark Kirk, one of the top House targets from Democrats in 2008 and 2010, who managed to win even with Boehner's insistence on lockstep voting. Perhaps this is the new cursed seat, having changed occupants at least once per term since 1992 and changed parties every term after that, since Burr broke North Carolina's. Anyway. Blagojevich was eventually impeached, nearly unanimously, by both chambers of the Illinois state legislature: the House voted 114-1, and the Senate 59-0. The Senate voted separately to bar Blagojevich from holding any future political office in Illinois.
Frank Church is the only Democrat ever reelected to the Senate from Idaho, serving from 1956 to 1980. Despite representing a very conservative state, Church was quite liberal, working with then-Majority Leader Lyndon Johnson on the Civil Rights Act of 1957 (before that, Church had royally pissed off Johnson by voting on something for which his vote was not desired, and the dude ignored him for six months); though it was too weak to do much of anything, Johnson rewarded Church for his help by giving him a seat on the Foreign Relations Committee, from which Church launched a steady effort against the Vietnam War. He was also instrumental in the creation of the modern system of federally protected lands, one of which in Idaho was renamed for him weeks before his death - the Frank Church-River of No Return Wilderness; apparently Idaho didn't have any areas with more pleasant names available. In 1976, Frank Church ran for President; he ultimately withdrew in favor of Carter, but he was on the short list for Carter's running mate. He also is the only Idahoan to win a major party's primary. Unfortunately, his efforts to return the Panama Canal to Panama in the seventies were appreciated neither by his constituents nor by conservative groups, and he was defeated narrowly in 1980 amidst Ronald Reagan's easy victory, overwhelming in Idaho.
Since then, Idaho has had no Democrats in the Senate, and only two Democrats in the House, one of whom, Walt Minnick, served quite recently. Minnick won largely because of his opponent's unpopularity - Bill Sali was called an "absolute idiot" by his colleagues, and one of them said that he had wanted to throw Sali out the window when they were in the Idaho state legislature; thus, Minnick was unlikely to be reelected, barring a very strong year for Democrats nationally (which was certainly not the case in 2010) or something interesting happening, like Sali managing to win the Republican nomination. In that climate, though, he could easily have mounted a challenge from the far right and be supported vigorously by the teabaggers, who are almost certainly stupid enough to root for the one guy who could possibly lose (cf. O'Donnell in Delaware). Anybody who calls Newt Gingrich a RINO has the intellectual capacity of wet gravel. Amazingly, a member of Idaho's House, Raul Labrador, won the nomination and ran on being even crazier than Sali; Labrador and Minnick were about even in the polls in the while, and then Minnick apparently drank paint and tried to out-conservative Labrador, who proceeded to beat him.
Speaking of Democratic Senators from states that are deeply red today, Frank Moss was elected to the Senate from Utah in 1958, winning with less than 40% of the vote; he faced the two-term incumbent Arthur Watkins, whom a former two-term governor tried to primary because Watkins chaired the committee that censured Joe McCarthy, and the governor still ran as an independent, splitting the large conservative vote. However, somehow Moss managed to get reelected twice, the first time against the president of Brigham Young University, which in Utah is a pretty important person [insert Mormon joke here]. The power of incumbency, I guess, coupled with getting lots of money and water for Utah, which has never had a whole lot of either. He failed in his attempt for a fourth term, smacked down by Orrin Hatch, who's quite likely to lose the nomination for his seventh term, if he doesn't decide to retire before he can be kicked out.
We think of the Senate as being a very prestigious body nowadays, but one of the very first Senators, Charles Carroll of Carrollton (Pro-Administration from Maryland; there were no formal parties at that point, though it wouldn't be too much longer before the Federalists emerged), served only from March 4, 1789, to November 30, 1792. See, Carroll had been serving in the Maryland Senate since 1781, and he liked it. When Maryland passed a law in 1792 banning any man from holding office in the state and national legislature simultaneously (New York did the same thing several years later), Carroll duly resigned one of those offices, and left the U.S. Senate. To be fair, D.C. was a swamp back then — literally. The city of Washington D.C. was a very unpleasant environment physically: no smog yet, but lots of heat, humidity, and foul stenches from the bogs. No air conditioning back then, either; in fact, there was a fight over air conditioning when it was commercially available, since some members felt that it was A. change, and change is bad, and B. a bad idea to make Washington any more comfortable and encourage career politicking. Naturally, comfort won, continuing a precedent that has lasted over two centuries, most often embodied by raises in the Congresscritters' salaries - which is now in the form of a Cost-of-Living-Adjustment, or COLA, since the 27th Amendment prohibits them from taking advantage of salary increases before a full session of Congress has passed. It took maybe a year or two for them to figure out how to circumvent that, which is really kind of sad.