With wins in 10 of the first 15 states to vote, Clinton has built a clear lead in the Democratic nominating contest -- and with several large, favorable states on deck in the next two weeks, she could soon make it nearly impossible for Sanders to catch her.
So Clinton, increasingly confident that she'll be the Democratic nominee, is turning her attention more and more to Republican frontrunner Donald Trump.
There's just one problem. Sanders isn't going anywhere.
"All the pundits are calling the race for Clinton. That means we're probably going to win in a landslide," Sanders said at a rally Wednesday in Portland, Maine.
Clinton is looking for ways to bridge her party's divide and bring Sanders' supporters into her fold ahead of a general election in which she'll need young voters and liberals to turn out in force.
"I congratulate Senator Sanders on his strong showing and campaigning and I am grateful to all of you who have voted for me," she said in her Super Tuesday night speech, extending an olive branch to the Vermont senator's supporters.
But dropping her criticism of Sanders could amount to unilaterally disarming.
Democrats have two debates on the docket within the next week -- Sunday night in Flint, Michigan, and Wednesday in Miami. Sanders has previewed his line of attack on the campaign trail in recent days by pressing publicly for Clinton to release transcripts of paid speeches she gave to Wall Street firms like Goldman Sachs.
Then there's the map.
The Michigan primary on March 8 is a key Sanders target, but Clinton's allies hope he enters the killing fields on March 15. That's when Florida, Illinois, Ohio, North Carolina and Missouri vote -- five states with sizeable minority populations, which have largely backed the former secretary of state. Clinton could win most, or even all, of them.
However, if Sanders survives and wakes up March 16 still within striking distance, he'll have no reason to bow out anytime soon. The race then shifts west to states that look more like Colorado, where he won handily on Super Tuesday.
And finally, there's his well-oiled online fundraising machine, which with free air time from scheduled debates and his ability to continue to rack up delegates is likely to keep operating, allowing him to stay in the race.
Sanders outraised Clinton $42 million to $30 million in February. And though his path to the Democratic nomination has narrowed, the money still appears to be flowing.
Sanders insists he's sticking it out through the convention. With huge delegate blocs to be awarded in New York in April and California in June, he'll be tough to mathematically eliminate.
"We've got a long way to go. Our plan is to win and win consistently between now and June. If we do, we believe Bernie Sanders will have more pledged delegates," Sanders senior strategist Tad Devine said Wednesday.
And Sanders campaign manager Jeff Weaver argued that his Super Tuesday victories -- Colorado, Minnesota, Oklahoma and Vermont -- demonstrate Sanders can win among Latino voters and in rural areas.
"There was a great diversity among the states that we won last night," Weaver said.
In the next week, the Sanders campaign is focusing on Maine, Kansas, Michigan and Nebraska. Weaver expects Maine's caucus to go favorably for them. He called the Michigan primary a "critical showdown" on working-class issues.
He acknowledged Sanders' biggest weakness as well, saying: "We have to do better with African-American voters between now and the end of the process. Clinton has done really well. But we think we can do a lot better."
Clinton's top aides are well aware that given Sanders' fundraising prowess and deep liberal support, he isn't going to drop out anytime soon. But Clinton's large operation now hopes to make it nearly impossible for him to win the presidency.
"The scenarios in terms of the margins he would have [needed] to win the remaining states will become less and less likely and that is probably true after March 15 or so," Brian Fallon, Clinton's press secretary, said on Tuesday. "He is going to have some victories tonight and he is going to have some victories in the week ahead. So he is going to have some state wins to point to, but we will continue to remind folks that the race is determined by delegates."
Clinton's operation feels it has invested wisely in key states, knowing that the nominating contest is a race for delegates, not individual victories.
And, when asked, Clinton aides are more than happy to note that Sanders has been unable to win African-American and Latino voters, the buzzsaw that his campaign has known was coming for months but was unable to avoid -- with losses in South Carolina followed by a swath of Southern states on Super Tuesday: Texas, Virginia, Georgia, Alabama, Tennessee and Arkansas.
"You can't win the nomination writing off the most diverse states," Fallon said Tuesday night. "That is a big message from tonight. For better or worse, they only contested five of the 11 states and the ones they effectively ceded happen to be the most diverse."
That said, aides are eyeing the rest of the calendar cautiously, aware that Sanders could pick up wins in the coming week, with contests in Kansas, Louisiana and Nebraska on March 5, Maine on March 6 and Michigan and Mississippi on March 8.
But don't expect Clinton to step up her rhetoric against Sanders. She will draw contrasts with him on college spending, health care and guns -- especially at the two upcoming debates -- but she will primarily lead with a positive message on the stump, aides said.
"She talked the other day how we are taking this campaign national. I think a lot of the markers have been laid on a lot of what the core contrasts are on this campaign. There will be a couple debates in the next 10 days and I am sure some of those differences they have will manifest themselves and surface again," Fallon said.
"But in a phase of the campaign where we are not truly running a national campaign and in some of these states she has the opportunity to be there only for a brief period, we are going to lead with our affirmative message," he said.