Bernie Sanders has been considered an underdog in the Democratic Primary elections since he announced his candidacy. Leading up to the first state primaries, his grassroots movement picked up steam particularly among younger voters. When voting started, he did win in New Hampshire, but Hillary Clinton picked up more states, particularly on Super Tuesday. Clinton has a strong advantage in the South, where she won Alabama, Arkansas, Georgia, Tennessee, Texas, and Virginia.
This firmly put Sanders in a position where he has to win states that are in his wheelhouse, which is the Northeast (Sanders represents Vermont in the Senate). This made losing Massachusetts a significant blow to his campaign, but picking up Maine has reaffirmed his advantage in the area. The Maine caucus showed a massive advantage for Sanders, taking 64.3% of the vote. The result gave him 15 of the state’s delegates, while Clinton received 8. Prior to the Maine primary, Sanders also won Kansas and Nebraska.
These victories may have primed Sanders to win in Michigan, which is being considered a historic victory considering that polls had Clinton winning the state by a sizeable margin. March 15th should prove to be a major tipping point in the primary, with Florida, Illinois, Missouri, North Carolina, and Ohio all holding elections on that day. Ohio and Florida are notable for being big swing states in the general election. Certainly, Sanders also has his eye on upcoming primaries in New York and California, which carry a big number of delegates and have large liberal populations.