Democrat, Lyndon Johnson did not seek reelection, and therefore the democrats did not have the incumbent advantage in the race.
Herbert C. Hoover, the incumbent, for the Republicans and Franklin D. Roosevelt for the Democrats.
If the incumbent president wants to run again for president, it ultimately depends on the rules and processes within each political party. Both the Democrats and Republicans typically hold primary elections or elect delegates to decide their presidential nominees. The decision ultimately rests with the party members and voters, who will choose whether to support the incumbent president or opt for a different candidate.
Roosevelt's efforts backfired because in each case his candidate lost and the incumbent senator won the nomination and the November election.
They're not. Right now, the focus is on the Republican party because the Democrats have the incumbent, President Obama. The Republicans are deciding who will run against Obama.
The possessive form for the singular noun incumbent is incumbent's.
There's nothing that says that an incumbent president (or holder of any other office) is protected against challengers from within his or her own party. At the 1948 Democratic National Convention, there was an attempt to dump Truman (the incumbent Democratic president) in favor of Dwight D. Eisenhower (a Republican, though at the time the Democrats probably did not know this). However, Eisenhower flatly refused to run for either the Democrats or the Republicans, and the Democrats rather reluctantly realigned behind Truman (except for a small minority, the States' Rights Democrats or "Dixiecrats", who split off to support Strom Thurmond; if you've never heard of the Dixiecrats, let's just say they basically supported the US version of Apartheid). That said, the Democrats in 2012 decided not to mount a serious challenge to President Obama, and it turned out okay, since the president won re-election, defeating his Republican challenger Mitt Romney and winning a second term.
The incumbent is the current office holder, the "challanger' is the person running against the incumbent
The incumbent is the current holder of a political office. To vote "non-incumbent" would mean to vote for the challenger to the incumbent's position.
Barack Obama is the incumbent president.
No. President Barack Obama is Probably going to win, because he's an incumbent Democrat President, and most people probably think that Candidate Mitt Romney (Republican) is out for the rich, while President Obama is for the middle class. There are more Democrats than Republicans and incumbent Presidents tend to get reelected unless they are considered losers like Jimmy Carter and George H.W. Bush. It's very rare for an incumbent President to lose a reelection.
The incumbent in an election is the current office-holder. For the 2012 Presidential race, the incumbent is Barack Obama.