(CN) - Sen. Bernie Sanders didn't only win three Democratic presidential preference contests on Saturday, he kicked off a surge in donations that added $4 million to his war chest in less than 48 hours, his campaign announced Monday afternoon.
"It gives us the resource to compete in Wisconsin .. and to continue to compete right on through California and the District of Columbia in June," said Jeff Weaver, Sanders' campaign manager, during a conference call with reporters.
The campaign also noted that since March 15 the Vermont senator has won six of the last seven contests, all of them by significant margins. His latest three victories were in Alaska, Hawaii and Washington state.
"What that tells you is that reports of our death have been greatly exaggerated," Weaver said.
"We are in it to win it, and there certainly is a path to do so," he said.
That path means going toe-to-toe with Hillary Clinton from here on out, including in critical contests in Wisconsin next week and in New York on April 19.
Weaver said Sen. Sanders will be spending "a tremendous amount" of time in Wisconsin, a strategy that helped him overcome a significant deficit in the pools and pull off a surprising come-from-behind victory in the March 8 Michigan primary.
"What we saw in Michigan is that when the senator spends a tremendous amount of time in the state, explaining his positions, it excites the Democrat base and large numbers of people are moved to support him," Weaver said.
"We believe the same will hold true in Wisconsin, then we'll move on to Wyoming, which holds a contest just a couple of days later, and then it's on to New York State where we are making a big commitment," he continued.
"Bernie is a native son of Brooklyn, in many ways he is the voice of New York, and we will be competing [for every vote," Weaver said.
Sen. Sanders has challenged Clinton to a debate in New York, and on Monday, his campaign chided the former secretary of state for being slow to rise to his challenge.
"We agreed very late in the game to a debate in New Hampshire in exchange for three subsequent debates, Weaver said. "One of those, a debate in Michigan, has already occurred. What we've proposed is that the second debate be in New York, and the third, in California."
"We hope her campaign will relent and allow the people of New York to experience the debate between them," he said.
But the next speaker on the call, Sanders campaign pollster Ben Tulchin, then went on to mention several reasons why Clinton might not be eager to debate their candidate.
"Since March 15, Clinton's negatives in the polls have gone up, while Bernie's have gone down," he said. "Part of that is due to his being seen as uniquely honest and trustworthy, particularly when compared to [Donald] Trump or Clinton," Tulchin said.
"The other thing we're continuing to see in the polls is that Bernie is extremely popular with independents, while Clinton is not," he said.
Where this especially comes into play, Tulchin said, is in polling that looks ahead to performance in the general election.
"This has been consistent for several months," he said. "Bernie runs much better than Clinton, beating all three potential Republican candidates, where she does not."
Weaver picked up Tulchin point when he returned to the microphone moments later.
"Things are starting to get baked into cake here," the campaign manager said. "And Hillary Clinton is a weakened frontrunner."
The Sanders campaign insists that the perception of Clinton's lead is misleading, not only by the superdelegate count support the campaign sees as somewhat fungible but because early on they made a tactical decision not to aggressively compete against Clinton in the South, which they conceded as her base.
"Almost all of her pledged delegate advantage which we believe is 268 delegates comes from the eight states in which we did not compete," Weaver said. "But it has been an entirely different story in states where we have competed.
Sanders believes if he can win or at least do well in Wisconsin, New York, Pennsylvania and California, he can still secure the nomination.
"As I said, we intend to compete all the way to California and the District of Columbia, and that her advantage in pledged delegates will diminish with every contest," he said.
Weaver added: "If you want to be the nominee of the Democratic party, you need to consistently prove your strength ... I think what people are seeing now is that where a true competition takes place, Hillary Clinton is emerging as a much weaker candidate."
Clinton holds a large lead among pledged delegates but Sanders says those states and the California primary on June 7 offer him a path to compete for the Democratic nomination.
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