MILWAUKEE — Hillary Clinton seems to think that if she just ignores Bernie Sanders, maybe he’ll go away.

The Democratic front-runner, so weakened that the two are basically even in Iowa and New Hampshire, is marching ahead with planned attacks against Republican contenders, man by man, making no explicit criticism of her main primary opponent.

The aim, according to strategists and fundraisers close to her campaign, is to make Clinton look like she is already the party’s standard-bearer, and to convince voters that she, not that self-identified socialist Vermonter, is the Democrat best positioned to take on any of the GOP contenders.

“It reminds the electorate — it reminds Democrats — what the election is really about,” explained Democratic National Committee member and Clinton bundler Robert Zimmerman. “Every time she’s out there speaking about policy and drawing those contrasts, it’s a win for Democrats."

But some donors and backers are beginning to doubt her approach. As more and more polling rolls in showing Sanders matching or topping Clinton in both of the early voting states — and Democratic power brokers are beginning to acknowledge that she could lose there — Clinton’s campaign is coming under pressure to not just talk about taking the primary seriously but to start acting like it, too.

In private conference calls and closed fundraisers, some donors are telling Clinton’s brain trust something it certainly already knows: that Sanders’ rally shows no signs of slowing. He’s thrown some spiky roadblocks into what was once seen as her glide path to the nomination. And now it’s time, they say, for a strategy shift.

Clinton’s surrogates dismiss these concerns as unsurprising but unwarranted. “People start worrying when they look at these poll results,” said former New Mexico Gov. Bill Richardson, a Clinton opponent in 2008 who now supports her. “But the primary and caucus are a long way away. I think she’s turned things around with her Iran speech and the email apology. She should let that play out."

Richardson’s reasoning reflects her talking points. The Clinton team is worried, but it insists it’s not ready to materially change course. Clinton’s advisers and people familiar with her strategy say she will begin talking about what differentiates her from Sanders as the first Democratic debate gets closer, but that’s about as aggressive as she’ll get.

They’re confident, they say, that the nomination is hers — once she gets past the continuing questions about her State Department email arrangement. So why antagonize the Sanders supporters that Clinton will need come November 2016 by going public with the criticisms they’re airing in private?

“There’s a strong consensus not to go after him,” explained one close Clinton friend.

“I just don’t sense as much of a panic from them,” said another campaign fundraiser in close touch with the political operation.

But to the donors encouraging Clinton’s team to step up its game, that’s a dangerous attitude. Sanders appears to still be on the rise, and the controversy surrounding Clinton’s email practices as secretary of state show no sign of dissipating, these hand-wringing donors remind the campaign team. And a Thursday Quinnipiac poll of Iowa that has Sanders effectively tied with Clinton in the state for the first time has added urgency to their appeal.

The front-runner has yet to mention her main rival by name on the campaign trail, let alone draw explicit contrasts. That wasn’t expected to change on Thursday evening as Clinton rallied here in progressive Wisconsin, the state where it first became clear that Sanders could become a force to be reckoned with. It was here that a state party convention straw poll showed him closely trailing the front-runner in June, and it was here where Sanders drew one of his first enormous crowds — nearly 10,000 in Madison.

Clinton has more openly criticized Sanders in private conversations behind closed doors, said donors and allies who have spoken with her recently. But on the campaign trail her focus is squarely on Republicans. And her debut in Wisconsin was widely seen as a message to the state’s governor, Scott Walker.

Clinton has been needling the governor for months, letting the frequency of her barbs dip in line with his drop in the polls. But her Thursday visit to Wisconsin, which doesn’t hold its Democratic primary contest until April and hasn’t voted for a Republican presidential candidate since 1984, is her clearest shot yet across Walker’s bow. 

Her trips to other Republicans’ home turf have been less pointed because their states either vote earlier in the Democratic nominating process or hold particular influence as swing states — or, in the case of Bush and Rubio’s Florida and John Kasich’s Ohio, both. But this one, on the heels of another quick stop in Ohio, is not a delegate-collecting endeavor. It instead provides her with an opportunity to excite a group of Democrats that her campaign has been targeting, at a time when she could use a jolt of support.

Clinton officials told reporters last week that the campaign would start making Clinton’s policy disagreements with Sanders more clear as the shadow of the Oct. 13 debate looms larger. Their staunch refusal to knife Sanders comes largely from a long-standing sense of relief that it’s Sanders — and not a better-known candidate like progressive hero Elizabeth Warren — capturing liberals’ attention. They don’t believe the majority of Democratic voters would ultimately support a self-identifying socialist.

Accordingly, Clinton still maintains large leads in national polling and in most states outside of the first two.

“Any attempt to criticize him will offend Democrats and ultimately we will need them on the team,” said Clinton friend and donor Jay Jacobs. “When you get into talking about opponents on the Democratic side, it takes away from your message and it draws oxygen out of the room. And it doesn’t do anything other than alienating his supporters."

What’s more, Sanders supporters largely don’t see themselves as anti-Clinton (96 percent said they support him for his ideas in a recent Des Moines Register/Bloomberg poll of Iowa Democrats, compared with just 2 percent who said their Sanders support was a rebuke to Clinton), so she is reluctant to jeopardize that goodwill.

And members of the Democratic establishment backing Clinton also say the stark contrast between the party’s relatively orderly nomination process at the moment and Republicans’ free-for-all is useful, as well. 

“Bernie Sanders isn’t criticizing her, so there’s no sense in getting into a fight,” said Richardson. “It’s a good contrast with the Republicans fighting each other."

But that confidence is cracking among some Democrats who now believe Clinton’s national organization would have serious trouble staying intact if Sanders were to win Iowa and New Hampshire.

And Clinton, for one, showed no signs of conceding to such worriers on Thursday.

“If [Donald Trump] emerges, I would love to debate him,” she said earlier in the day in Columbus, Ohio. She didn’t acknowledge, however, that she still has to win a primary to get that far.