House Minority Leader Nancy Pelosi (D-Calif.) on Thursday reminded her Democratic colleagues not to go down the road of impeachment talk. “I don’t think we should be talking about impeachment. I’ve been very clear right from the start,” Pelosi said. “On the political side I think it’s a gift to the Republicans.”

Her main reason, she says, to stay away from impeachment is that Democrats need to stick with their political playbook. “We want to talk about what they’re doing to undermine working families in our country and what we are doing to increase their payrolls and lower their costs.”

She’s right that jobs and the economy remain at the top of the lists of voters’ concerns, but Democrats talk about other issues not front-and-center for most voters (e.g., immigration), so why not impeachment? There are a bunch of reasons.

First and foremost, Democrats have no idea what special counsel Robert S. Mueller III has. No one is really certain whether the Michael Cohen raid, for example, is about Cohen’s solo business dealings (as President Trump said) or about Trump, as well. No one knows what will come out in the Paul Manafort trial.

Second, Democrats don’t want to be mini-Trumps, prejudging evidence and making grand pronouncements about things they do not know. If they (rightly) criticize Trump for trying to force a particular outcome in the Mueller probe, they need to keep quiet. Put simply, if obstruction of justice is going to rest in part on hyperpoliticization of the Justice Department and FBI, Democrats want to keep their hands clean.

Third, no one knows if impeachment will be politically viable. After the midterms, we will have a much better idea as to how the country feels about Trump and whether Republicans will pay a price for partisan blocking and tackling for Trump. Democrats at that point may decide that impeachment should only be undertaken if there is a reasonable chance of conviction in the Senate. Otherwise, Trump emerges “vindicated.”

Fourth, Dems can certainly say that while public evidence of obstruction in their minds requires a congressional response, the degree of punishment required to reset our democratic system is to be determined. Will Trump admit to certain facts? If for example, Trump winds up signing a bill to protect Mueller (unlikely, but not impossible), his defense against obstruction gets stronger but congressional sanction for his original decision to fire FBI Director James B. Comey would be entirely reasonable.

Fifth, timing is everything. Suppose there is a prolonged court fight over obtaining Trump’s testimony (quite likely). The investigation drags out into 2019. Trump declares he won’t run for reelection. (Because he accomplished more in four years than any other president in history!) Is it worth it to impeach him with 12 months or so left in his term? Instead, his conduct becomes a central issue (a winning one for Democrats) in the 2020 election and a severe liability for Republicans who enabled him every step of the way.

Sixth, Democrats would do well to make the point that Republicans have proved themselves incapable of putting country above partisanship. In appealing to voters as the grown-ups and offering to restore sanity and comity, Democrats would do much better to run as the only party to hold Trump accountable, rather than the only party determined come hell or high water to drag the country through impeachment hearings.

As passionately as Trump critics feel about impeachment, the calculus for those who would vote in the process — House and Senate members — is fundamentally different. They’ve got plenty to lose if they make up their minds about an unknown fact pattern months, if not years, before the political terrain is ascertainable.