It's unclear how the momentum gained by Clinton on Tuesday will factor into those contests. The former secretary of state won at least four of the five primaries, in Florida, Ohio, North Carolina and Illinois. Clinton also had a narrow edge in Missouri, though Sanders could request a recount there.



Clinton's campaign also acknowledged Wednesday that Sanders could have an upcoming winning streak but expressed no worry about Clinton maintaining a solid lead in the delegate count. In the Democratic race, delegates are awarded on a proportional basis, making it difficult for a candidate to catch up once he falls behind.



"Looking ahead to the rest of March, Sen. Sanders is poised to have a stretch of very favorable states vote, including 5 caucuses next week, which he is likely to win, and the primary in Arizona, in which he has invested more than $1.5 million in ads," Clinton campaign manager Robby Mook wrote in a memo to supporters. "Our pledged delegate lead is so significant that even a string of victories by Sen. Sanders over the next few weeks would have little impact."