(CNN) What do Democrats really want from special counsel Robert Mueller's investigation?

It's a simple enough question, but the answers can be complicated and conflicting. The most obvious, and prevalent, would be the "smoking gun" -- proof positive that President Donald Trump personally negotiated or signed off on the terms of Moscow's meddling in the 2016 election.

The reality, of course, is that Mueller is unlikely to turn up anything quite so bold. And even if he did, Trump and his loyalists are unlikely to throw up their hands, pack their bags and hand over the White House keys. Republicans in Congress have done nothing to suggest they would press the matter. Democrats know this, so they seem to be pursuing a milder, and perhaps wiser, course.

As Mueller escalated on Monday, indicting Trump's former campaign boss and one of his deputies, while also revealing he'd made a "proactive cooperator" out of a foreign policy adviser to the campaign, Democrats mostly kept their heads down. Rather than focus on Trump and Paul Manafort, they sought to fortify the special counsel's mandate.

Statements from top Democratic officials in Washington suggested the party line is, at the highest levels, focused on putting the process ahead of the politics -- to reinforce the guardrails rather than try to map out the road ahead.

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