candidates are not 'nominated' by parties to run in primaries. they run of their own accord and are nominated by the party if they win the primary. there is no realistic possibility of an incumbent president being defeated in his own party's primary unless he is extremely unpopular. even bush with his 23% approval would probably have won the republican primary had he been able to run again. most americans know this. which means what the democratic respondents where probably expressing was a desire to see a more liberal candidate run against obama to force him to recommit to liberal positions which he has moved away from in order to win in his own party's primary. the author either doesn't understand this or is being intentionally misleading.
Yemen's Houthi rebels commit to peace plan in letter to UN chief, BBC reports (Haaretz)
from the article: Democrats split on whether Obama should serve a second presidential term