The indictment of Donald Trump's former campaign chairman and the guilty plea entered by a former low-level foreign policy adviser seemed to hand Democrats a weightier cudgel with which to club the president's party this week. But even though special counsel Robert Mueller's Russia collusion probe is picking up steam, Democratic strategists and campaign operatives are urging party members to tread carefully.

Research in the form of focus groups, polling, and on-the-ground conversations conducted by various Democratic groups suggests that reaction to GOP policy will drive their voters more effectively than the ongoing Russia investigations, however newsworthy they have become. Democrats figure that the eventual conclusions reached by Mueller and congressional committees will speak loudly for themselves. In the more immediate term, many Democrats argue the party will be more successful in its electoral efforts by focusing on economic issues that matter to everyday voters.

The newly unveiled tax proposal put forth by Republicans on Thursday figures to be something of an organizing principle among the Democratic base. Democrats prided themselves on the failure of Republican efforts to repeal Obamacare. But they acknowledge that blocking the tax legislation will be a much steeper hill to climb. While several key obstacles for Republicans remain, Democrats fear the GOP will be more united around the tax bill than they were around the health care legislation.

The lack of legislative accomplishments so far has added to pressures on Republicans to pass the tax overhaul, raising the stakes for them to get in line, and quickly.

"In terms of Republicans, this is what they really care about. The real Republican issue is taxes, so it's definitely going to be a harder lift [for Democrats] because Republicans are going to try to stay together on this," says Angel Padilla, policy director for the resistance group Indivisible.

"Yes, the investigation is incredibly important and Mueller is doing his job, but what's happening in Congress isn't slowing down -- it's actually speeding up," says Padilla. "The only fight in Congress right now is on taxes. That is where the energy needs to stay."

Framing the tax debate should be the focus of paid media efforts, some Democrats say.

"While top Trump aides getting indicted is decidedly bad for Trump and the Republican Party, Democratic candidates still need to be making the arguments that resonate with voters on issues that impact their lives," says Josh Schwerin, spokesman for the super PAC Priorities Action USA. "In the focus groups we’ve been conducting across the country we’ve consistently seen that the most potent messages, both for persuasion and mobilization, are on issues that directly impact people’s lives like health care and tax reform."

Democratic campaign strategists see the tax debate as more influential than the Russia issue in many Republican districts they hope to flip, specifically seats in California, New York and New Jersey. Republicans in those high-taxed states have expressed opposition to proposals to eliminate deductions for state and local taxes. While no Republicans from California defected on the budget vote last week -- needed to permit tax reform to proceed under the reconciliation process -- several from New York and New Jersey did. The GOP bill would allow residents to deduct state property taxes but not income taxes.

"Candidates have been very focused on health care and on middle-class tax increases, much more than indictments," says one Democratic campaign operative. "Your average everyday American isn't thinking about this day in and day out."

Bernie Sanders echoed that sentiment during an appearance on NBC's “Late Night With Seth Meyers” Monday, after the indictments came down. "Americans are not staying up every day worrying about Russia's interference in our election. They're wondering how they're going to send their kids to college. They're worried about how they're going to be able to pay the rent. They're worried about whether they can afford health care," he told the host.

That's not to say Democrats don't think the advancements in the Russia probe are detrimental to Trump and Republicans and helpful to their own prospects.

"There is no question that the president's approval rating has a lot to do with how well Republicans do in the midterm elections. And there's also no question the Russia issues have played an important role in doing great damage to the president's approval rating," says longtime Democratic pollster Mark Mellman.

"That doesn't mean individual candidates should be talking about Russia all the time, because people are not voting for them specifically because of Russia and the fact that Trump may have done wrong," Mellman says. "I would tell my clients, you don't need to talk about Russia, but our party leaders and the press we want to be talking about Russia because it keeps those things in the news."

For their part, leaders in Congress have been trying to quell talk of impeachment among some members and top donors like Tom Steyer so as not to overreach, and to keep the conference focused on policy. They have also advocated for Mueller to continue his work undeterred, and have been messaging against efforts by some Republicans to curb the special counsel's resources. Democrats have also been pressuring Trump not to interfere with Mueller's probe, though the White House has indicated the president has no plans to fire the special counsel.

"We're focused on making sure that Robert Mueller can do the job he needs to do, to figure out if there was an attack on our democracy," DNC Chair Tom Perez told reporters earlier this week. "Our focus is on this attack on our democracy and making sure we hold accountable who was involved, and then equally importantly, making sure we never let it happen again."

Research conducted in August by the Democratic firm Greenberg Quinlan Rosner shows that protection of the special counsel and related congressional investigations from executive interference resonates with a broader audience. In a memo explaining its research, the firm advised Democrats to frame their messages around that principle when it comes to Russia. The authors of the study say Democrats should not invoke impeachment. But, they should stress the importance of Russian meddling in elections, particularly the national security implications, and to call for bipartisan actions. But the research also suggested parts of the Russia issue could be effective in elections, particularly questions raised regarding Trump aides’ veracity.

Efforts by the president and conservatives to downplay the investigations aren't resonating with the broader public, according to a new Washington Post-ABC News survey. Fifty-eight percent say they approve of Mueller’s handling of the investigation while 28 percent say they disapprove, the poll finds. Notably, 49 percent think Trump himself may have committed a crime in connection with Russian attempts to influence the election.

Some Democratic activists argue that the party can pursue the Russia story and economic issues at the same time. "Democratic candidates can't use Russia as an excuse for why we didn't win in 2016. That is not helpful. ... But what I think Americans are very concerned about is whether Donald Trump was involved in criminal activity," says Charles Chamberlain, executive director of the progressive group Democracy for America.

"I definitely think Democrats should embrace and campaign on the idea of accountability," Chamberlain says. "But that can't be the only thing they talk about; they have to have a vision for the future."