Just days away from arguably the biggest moment of his political career, Senator Bernie Sanders is relatively sanguine on his chances for victory.

“We will win Iowa if there’s a large voter turnout,” Sanders told Lester Holt Wednesday in an exclusive interview with NBC Nightly News.

Turnout is something that Sanders returned to at several points in the interview. In many ways, he acknowledged, voter turnout is key to his campaign’s electoral success not just in Iowa but in virtually every corner of the country where his main rival Hillary Clinton enjoys the crucial establishment support and financial prowess that is often key in primary season.

Getting people to show up, however, has largely not been a problem for Sanders thus far in this whirlwind campaign.

Thousands have attended his rallies — from liberal strongholds like Los Angeles and Boston, to reliably Republican locales like Montgomery, Alabama — to hear his core message on income inequality and answer his call for a “political revolution” to bring change to Washington.

And the Sanders campaign claims to have received two and a half million individual contributions — more than any other presidential candidate in U.S. history.

On Grassroots Movement

In the interview, Sanders returned to the central tenets of his policy platforms: universal healthcare, free tuition at public universities and colleges and reforming what he calls the nation’s “corrupt campaign finance system."

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When asked how his ambitious proposals could get through in a gridlocked and Republican-controlled Congress, Sanders’ answer was two-fold.

He first cited experience working with his colleagues across the aisle, highlighting what he called a “significant piece of legislation” providing comprehensive health care to veterans which he worked on last year with Sen. John McCain (R-AZ) in the House Veterans Committee.

"I can work with Republicans," he said.

The second factor, he said, was bringing millions of people into the political process to demand that Washington “starts representing ordinary Americans, the middle class [and] working families — not just the billionaire class.”

Entrenched interests in Congress, he said, were such that if free tuition is to become a reality, students would have to stand up and fight for it. If the issue of equal pay in America were to ever come to fruition, women would need to stand up and fight for it. As he has throughout his unlikely grassroots campaign, Sanders appeared confident that if ordinary Americans unite in their struggles, true reform could break through the various obstacles.

On Foreign Policy

On a day where Sanders held a private meeting with President Obama in the White House, which he admitted felt a little different visiting as a presidential candidate, the senator was slightly more retrospective on an issue where he has come under criticism: national security.

“When you sit in the Oval Office, where I was today, “ said Sanders. “You understand that the issues are not just the mess — the need to rebuild a disappearing middle class, the need to make sure that all of our kids, regardless of income, can get a higher education, the need to deal with poverty — but also, we are living in a very, very dangerous world.”

He said he and the president spoke about foreign policy but did not divulge details. He did repeat his pledge to destroy ISIS, but was careful to stress his support for a strategy that did not “get us involved in perpetual warfare.”

This is where he said he differed from Clinton. He pointed out, as he often does in nearly every stump speech on the trail, that Clinton voted for the Iraq War. Sanders voted against it.

"What I said back in 2002 — much of what I predicted would happen, the destabilization, et cetera, turned out to be right," said Sanders.

Looking Ahead

He was defiant about his prospects for Monday night in Iowa: If he comes in second place, he said, his campaign would move full-steam ahead to New Hampshire, Nevada and South Carolina — the next three primaries on the calendar.

At stake, he repeated, was nothing short of a political revolution. He then again returned to his familiar refrain: turnout was key.

“If voter turnout remains low, if working people give up on the political process, then the big money interests dominate,” Sanders said. “That’s the political dynamic that we're trying to change.”