Joe Biden widened his path to the Democratic presidential nomination and narrowed Bernie Sanders' as a result of primaries Tuesday in six states. The former vice president won four states, including the battleground state of Michigan, the prize in the Democratic presidential primaries. Sanders won North Dakota's caucuses and was trailing Biden in a second count Wednesday of ballots in Washington, the second-largest delegate prize in Tuesday's primaries.

Biden's decisive wins in Michigan — a state Sanders won in 2016 with his insurgent campaign of democratic socialism — along with Missouri, Mississippi and Idaho dealt a serious blow to the progressive left's last hope in the Democratic nominating process. Together, the six states were allocating 352 delegates, 125 of them in Michigan.

As he did in South Carolina and Super Tuesday primaries, Biden showed strength among working-class and African American voters who are vital to winning the Democratic presidential nomination.

Tuesday's primaries were the first in a newly configured, two-man race. Biden now holds a substantial, 161-delegate lead, a dramatic reversal after his campaign hadn't won a single primary in three starts and appeared on the brink of collapse before his South Carolina and Super Tuesday surges.

Biden's wins build on a quickly assembled coalition of moderate and establishment voters. He went into Tuesday's voting leading Sanders 664-573 in the delegate count. The Tuesday primary counts so far expand Biden's lead to 842-681, making a path forward for Sanders not impossible, but difficult.

Under Democrats' primary system of apportioning delegates, as opposed to Republicans' winner-take-all system, Sanders could revive his flagging campaign and claw his way back to front-runner status. But he'll need to do well next Tuesday in primaries in Arizona, Florida, Illinois and Ohio.


over Sanders, 51 percent to 27 percent, gave the former vice president a boost heading into Tuesday's voting in Michigan.

Sanders, who has won all of the Western states that have held primaries so far this year, had better polling odds in Washington, but still poll, 47 percent to 44 percent among likely voters — but within the poll's error margin of 3.6 points.

The Sanders campaign had hoped to gain ground in the delegate race in Missouri, a state he lost by less than a percentage point in 2016, essentially splitting the state's 68 delegates with Clinton.

Roy Temple, a former Missouri Democratic Party chairman and a consultant for Minnesota Sen. Amy Klobuchar's now-suspended campaign, told the Kansas City Star he had expected the to be "a real nail-biter if history is any guide."

"We've seen this movie before," Temple told The Star. "There was a pretty stark ideological distinction between Bernie and Hillary, and it was a tie."

Noting that polling data has been volatile after Biden's Super Tuesday surge, the election forecasting site FiveThirtyEight forecast , but said margins matter. In Missouri, the FiveThirtyEight forecast gave Biden a 92 percent of chance of winning, with an average forecast 58 percent vote share, compared with an 8 percent shot at winning for Sanders and a 39 percent vote share.

In Mississippi, FiveThirtyEight forecast gave Biden a near-lock, with a 99 in 100 chance of winning the state with a 65 percent of the statewide vote, compared with 25 percent for Sanders. Mississippi allocates 36 of its pledged delegates to the national convention on the statewide total, and the remaining 23 are allocated according to votes in its four congressional districts.

Biden, who was leading Sanders by 30 points in all congressional districts, stood to collect a large share of Mississippi's district-level delegates, according to FiveThirtyEight.

Idaho Democrats used a primary for the first time to decide how to split up the state's 2o delegates. Sanders defeated Clinton in the caucus four years ago, and President Barack Obama easily defeated Clinton in 2008.

A primary was expected to boost , the Idaho Statesman reported, but either candidate would face tough odds against Trump in November. The last time Democratic presidential candidate to win Idaho in the general election was Lyndon Johnson in 1964.

FiveThirtyEight , where he was expected to pick up 57 percent of the vote in the state's Democratic caucus. Sanders is the unofficial winner of North Dakota.

The Associated Press contributed reporting.