On Sunday night, Hillary Clinton and Bernie Sanders will face off in their seventh debate, less than a week after Clinton expanded her delegate lead on Super Tuesday and in-between additional primaries and caucuses on Saturday, Sunday and Tuesday.

CNN will host the debate, which begins at 8 p.m. ET, from the Frances Wilson Library on the University of Michigan's campus in Flint.

Both candidates have repeatedly highlighted the water crisis in Flint during the campaign. Clinton has said that "what happened in Flint is immoral," and Sanders called on Gov. Rick Snyder to resign a while ago. The crisis dates all the way back to 2014 when a state-appointed emergency manager decided to switch Flint's water source from Lake Huron to the Flint River to save money. But the water from that river was corrosive and caused lead to seep into old pipes, which has left many Flint residents with long-term health effects associated with lead exposure and might have caused deadly cases of Legionnaires' disease.

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The debate will come just a day after voters headed to the polls or caucus sites in the Democratic race in Kansas, Louisiana and Nebraska, the same day as the Maine Democratic caucuses, and just two days before Michigan and Mississippi hold their primaries.

Clinton racked up a win in Louisiana's primary Saturday by wide margins, 71 percent to Sanders' 23 percent. But she also lost Nebraska and Kansas to her rival by several points in each contest.

The debate also will happen less than a week after Clinton had double-digit victories on Super Tuesday in Alabama, Arkansas, Georgia and Tennessee. She also picked up Virginia, a key swing state in a general election, and Massachusetts where it was considered a close race with Sanders. She also won Texas and Georgia by wide margins. Sanders won four states: Vermont, his home state, as well as Oklahoma, Colorado and Minnesota.

According to CBS News' latest count, Clinton has racked up 1,110 delegates while Sanders has 456. A candidate needs 2,383 delegates in order to win the nomination.

Sanders' campaign, however, is confident that they'll win some of the nominating contests coming up.

"We do not think the calendar ahead looks nearly as good [for Clinton] as [Tuesday]. Not a single day," said Tad Devine, Sanders' senior campaign strategist, on a conference call with reporters.

In Michigan, where the debate will be held, a CBS News battleground tracker poll shows Clinton with an 11-point advantage. Among likely Democratic primary voters, Clinton leads 55 percent to Sanders' 44 percent, according to the poll released Sunday. Maine's Democratic caucus results are also expected Sunday.

New developments on the federal investigation into Clinton's private email server also continue to plague the Democratic front-runner.

On Sunday, the Washington Post reported that Clinton had sent over one hundred emails while secretary of state that the government has since said contain classified information. And earlier in the week, the Justice Department offered immunity to Bryan Pagliano, the State Department staffer who helped set up Clinton's private server.

Clinton, for her part, said she believed the investigation's progress was a sign that "we're getting closer and closer to wrapping this up."

"I think that we'll be moving toward a resolution of this," Clinton told CBS' "Face the Nation"on Sunday.

The Republican race, meanwhile, has reached a new level.

Last weekend, after Trump failed to immediately disavow the Ku Klux Klan and its former grand wizard David Duke, Hillary Clinton said she was "disappointed" in the GOP frontrunner.

Sen. Lindsey Graham, R-South Carolina, told CBS News on Tuesday night that Republicans would lose to Hillary Clinton if Trump wins the party's nomination.

"We're going to lose," Graham said. "You'll never convince me that Donald Trump is the answer to the problem we have with Hispanics. It will tear the party apart, it will divide conservatism, and we're gonna lose to Hillary Clinton and have the third term of Barack Obama."

After this weekend's nominating contests, Trump has added two more state wins to his primary scorecard, while Ted Cruz has done the same. Florida Sen. Marco Rubio notched a win in Puerto Rico on Sunday.

→ What: Seventh Democratic presidential debate

→ Where: Flint, Michigan

→ When: 8 p.m. ET on CNN

→ On TV: CNN

→ Online: CNN.com

→ CBSN will have updates on the Democratic debate beginning at 8 p.m. ET

CNN's Anderson Cooper will moderate the debate.

