By Darren Samuelsohn, Politico–

Democrats vying for the White House want to talk about anything right now but Robert Mueller’s Russia probe. But the 2020 race is inevitably going to keep coming back to 2016 — and what the special counsel uncovers.

Behind the scenes, the candidates, campaign aides and consultants are already plotting how to publicly address the scandal that has consumed President Donald Trump. They know the campaign that gets it right could break free from the cluttered 2020 pack. In the early primary and caucus states, the Democratic hopefuls are already encountering “simmering, seething outrage” about Trump’s possible ties to Russia, said one strategist for a 2020 campaign. The candidate who taps into that anger could ride the wave to the nomination.

Speaking up could have disastrous ramifications, though. Much like Democratic candidates in the 2018 midterm elections, the party’s presidential hopefuls are wary of appearing consumed by — and politicizing — a scandal that grips regular Rachel Maddow viewers but seems confusing and distant from the kitchen tables of many Americans.

“Smart campaigns will war game this very quietly,” said Ben LaBolt, a former spokesman from the Obama White House and 2012 reelection campaign. “They’ll have smart plans on the shelf. But it’s not something they’ll talk about. It’s not something that they’ll broadcast.”

Democrats working for 2020 candidates describe Mueller’s work as something akin to a virus that will keep forcing their campaigns to take precautions.

“It’s the elephant in the room,” said the party strategist working with a White House hopeful, fretting about the uncertainties tied to Mueller, from the rumors about possible new indictments to the advice from inside their own campaigns to just stay quiet about the topic.

“The Russia issue is one that the political and pollster class says, ‘Stay away from right now.’ But ultimately the story will take us there and we will have to deal with it,” the Democratic strategist added.

So far, though, Democrats running to take on Trump have for the most part avoided Mueller. Instead, the candidates have used their precious few media moments to introduce themselves with optimistic narratives — love, inclusion, equal opportunity.

When Mueller does come up, the White House hopefuls often fall back on safe terrain, talking up their support for protecting the special counsel from presidential interference or to urge restraint among the party faithful who’ve been clamoring to impeach Trump before Mueller has finished his work.

“I really think we have to divorce that right now from any 2020 campaign,” Sen. Amy Klobuchar, the Minnesota Democrat expected to announce a White House bid on Sunday, told POLITICO. “Our democracy depends on allowing this investigation to be completed and finding out what a foreign country did and make sure that we do everything right, because this is now and 2020 is then.”

There are notable exceptions to the avoid-Mueller approach. Several senators in the 2020 mix who serve on the Judiciary Committee, including Klobuchar, peppered Trump attorney general nominee William Barr with questions about Mueller last month during his confirmation hearing. Casting a “no” vote against Barr, who refused to commit to releasing the special counsel’s findings in their entirety, is also viewed as an early litmus test for the White House hopefuls in Congress.

A few candidates have also sent subtle signals on the 2020 trail that they’re thinking about the Russia probe. During Kamala Harris’ campaign launch speech last month in Oakland, for example, the California senator hinted at the Mueller probe with a head nod: “We have foreign powers infecting the White House like malware.”

Perhaps the most blunt 2020 aspirant is Eric Holder. The former Obama attorney general has used Twitter and public remarks to deliver a running commentary on the Mueller investigation. Holder, who is expected to announce his White House plans later this month, has already said he thinks the special counsel has the legal authority to prosecute Trump for obstruction of justice. It’s a bold assertion that runs counter to decades of internal Justice Department policy dating back to Richard Nixon and Watergate.

A big challenge facing Democrats who do speak up about Mueller is the uncertainty and secrecy surrounding most everything he’s doing.

The special counsel has no deadline, and while acting Attorney General Matthew Whitaker recently said that the special counsel’s probe was “close to being completed,” the constant churn of new revelations suggests the investigations will reverberate until the general election. Former Trump aides Paul Manafort, Rick Gates and Michael Flynn still haven’t received their sentences despite pleading guilty, while longtime Trump associate Roger Stone is on track for his own criminal trial in the late summer or early fall in Washington, D.C., a spectacle guaranteed to generate nonstop media coverage and return attention to Mueller’s efforts.

The investigation’s inscrutability also means that jumping to comment on the latest Mueller revelation can boomerang quickly.

After Buzzfeed’s report last month that Trump had directed his personal lawyer Michael Cohen to lie to Congress, Holder swiftly tweeted that, if the story were true, “Congress must begin impeachment proceedings.” He wasn’t alone. Former Obama Housing and Urban Development secretary Julián Castro, asked about the story on ABC’s “The View,” replied, “I say, yes, if it’s true, then he should be impeached. But let’s not trip over ourselves, right? First, let’s make sure that it’s true, and that is going to happen in short order.”

A day later, Mueller’s office issued a rare public statement questioning the article’s accuracy. The rebuke gave Trump and his allies an easy opening to attack Democrats who had pounced on the news.

Politically, having smart responses ready on the Mueller front makes sense for Democrats who are already venturing to early primary battlegrounds like Iowa, New Hampshire and South Carolina. The 2020 strategist said that’s where candidates are encountering grass-roots anger about the Trump campaign’s encounters with Moscow. If big news breaks, they don’t want to be left out.

“Assuming that Mueller implicates Trump, there is going to be a rather instantaneous reaction by the whole field,” the strategist said. “You wouldn’t want to be the lone Democrat splitting hairs on the question.”

LaBolt, who currently is on the 2020 sidelines, said the White House field faces “danger in prejudging the investigation or overly politicizing it before we know the results.”

But he said the campaigns need to be preparing for all contingencies, including perhaps the most detonative scenario of all: a smoking gun that forces Trump and even Vice President Mike Pence off the 2020 ticket. “Behind the scenes, they’ll have a very good contingency plan in place for the Mueller investigation in case the findings are truly explosive, in case it calls into question whether he will remain president,” LaBolt said.

Scott Mulhauser, a former senior aide to Vice President Joe Biden who keeps in touch with several 2020 campaigns, said the Mueller probe will continually force the Democratic field to perform “an inherently odd dance” between sounding presidential about the special counsel’s need for space and speaking to a party base that wants Trump out of office by any means necessary.

“Everyone is wrestling with what to do with it,” he said. “The smart campaigns are thinking through this, planning and continuing to assess this in real time as it evolves, to figure out what they need to say and how they say it, to ensure viability and to ensure credibility at the same time.”

Historically, presidential campaigns of both parties haven’t shied away from using scandals as a way to boost support with voters, though the results have been mixed.

Republican Mitt Romney tried to hang a failed investment in solar energy company Solyndra around President Barack Obama in 2012, even traveling to the Bay Area company’s empty headquarters in the midst of the general election campaign to harp on the administration’s loss of a half-billion dollars in taxpayer money.

Just weeks before the 2004 election, Democratic nominee John Kerry’s campaign tried to score points off White House political adviser Karl Rove’s appearance before a Washington, D.C., grand jury investigating who leaked the identity of a CIA operative, saying President George W. Bush’s administration should “come clean about their role in this insidious act.”

Bob Dole in 1996 threw a kitchen sink worth of scandals at Bill Clinton in the waning days of their race, declaring in one closing argument speech, “Where’s the outrage in America?”

In each case, the strategy failed to significantly move the needle.

But President George H.W. Bush attributed his own reelection loss in 1992 to a late development in the Iran-Contra scandal, according to Bob Woodward’s 1999 book, “Shadow: Five Presidents and the Legacy of Watergate.” In an indictment against former Defense Secretary Caspar Weinberger issued just days before the election, prosecutors included a footnote declaring that Bush, as Ronald Reagan’s vice president, had actually “favored” the secret arms sales to Iran. The Clinton campaign seized on the revelation, which contradicted five years of Bush denials, as “a true smoking gun.”

“Scandals matter” in the course of any presidential campaign because they “allow opponents to seed the clouds of doubt,” said Frank Sesno, a former CNN journalist who asked Bush about the indictment during a live town hall interview broadcast just days before the 1992 election.

He also predicted the Mueller probe will stand out far more in 2020 than the other presidential scandals that have come in the post-Watergate era.

“We’ve not had a scandal where a hostile power has been implicated in the campaign or candidacy of a president. That is fundamentally different,” said Sesno, now the director of The George Washington University’s School of Media and Public Affairs. “I can’t imagine that this investigation will not be a constant companion of the campaign.”

Christopher Cadelago contributed to this report.