During the 2008 Democratic presidential primaries, when individual state in the U.S. have elections to choose the party‘s candidate, there were several interactions between Hilary Clinton and Barack Obama which made many feel uncomfortable. The interactions were direct, confrontational, critical, in some cases bordering on personal.
Within a week or so the two candidates had softened their tone. The media reported on it at length, speculating that senior people in the Democratic Party had advised Clinton and Obama to do so. They feared that if the attacks continued the winner of the primaries will be damaged going into the general election.
Candidates in the same party exposes each other‘s weaknesses offers opportunities for the opposing Republican Party. Hilary and Barack were asked to be more discrete.