WASHINGTON — If President Donald Trump fired special counsel Robert Mueller the first visible response would appear within hours, in the streets.
More than 500 demonstrations are already planned — outside the White House and the Capitol, in blue states and red states, in big cities, and in smaller places with names like Ketchum, Kankakee, and the pertinently monikered Truth or Consequences.
An email would go to tens of thousands of already-registered participants: "Moments ago, Donald Trump fired the man investigating Trump and his inner circle, special counsel Robert Mueller. Make no mistake: Trump has set off a constitutional crisis. Our immediate response will determine the future of our democracy."
The marches are planned for 5 p.m., or noon, depending on what hour the firing occurs. The demonstrators already have posters and chants like: "Law and order for who? Always for me, never for you."
The investigation into Russian election collusion led by Mueller, the former FBI boss, has made its first arrests, and is now burrowing into the president's inner circle — prompting an all-out assault by Trump allies alleging it is biased and has strayed beyond its original purpose.
This seven-day-a-week attack has fueled speculation he might be planning something: either firing Mueller or hobbling his investigation.
Trump can't fire Mueller by himself, and would have to reshuffle senior staff to find a willing executioner. His spokeswoman Sarah Sanders professes exasperation over the speculation: "For the 1,000th time, we have no intentions of firing Bob Mueller," she says.
Protest organizers aren't taking any chances.
They've been preparing demonstrations via progressive groups like MoveOn.org.
"We're telling people, 'Be ready.' We might have only two hours' notice (to protest)," says Kim Akins, who has signed up about 100 people to protest on a street corner in Youngstown, Ohio.
"If he fires Mueller it's about whether this country believes in the rule of law."
Mindie Keller is another organizer.
She was always interested in politics, but never active beyond the simple act of voting. That's changed under Trump, she says. Now she's preparing a Mueller-firing demonstration just outside Allentown, Pa., at the office of a Republican senator.
"I feel like it would be a breaking point," she said.
"(A firing) crosses the line of presidential power... (It says), 'I can do whatever I want.'... That's not what our founders wanted. They spent a lot of time designing a constitution, a system, to keep our president in check."
The protest plans illustrate potential blowback Trump would face for any such move.
An even greater threat than those protests, however, is the risk firing Mueller, or limiting him, would shift the battle to the home state of the president, the site of his corporate offices, and of his campaign headquarters: Democrat-controlled New York.
New York's attorney general hasn't denied reports his office has been co-ordinating with Mueller. Eric Schneiderman even hinted a few days ago, to The New York Times, that if Mueller gets fired, he might step in.
"If that happens, we'll do ... whatever we can do to see that justice is done," Schneiderman said.
Numerous federal laws relevant to the Russia probe do have replicas at the state level — money-laundering, conspiracy, obstruction of justice, and trafficking in stolen materials, like emails.
But some federal charges couldn't be prosecuted by state officials. Those no-go zones include failure to disclose foreign contacts on federal security forms; lying to the FBI; and election-law violations with forbidden foreign contributions.
The bottom line: firing Mueller wouldn't end Trump's troubles.
"That's right," said Ryan Goodman of New York University, ex-special counsel within the U.S. Department of Defense.
"And it could also create other problems for him."
Jens Ohlin, vice-dean of New York's Cornell University law school, concurred: "I would imagine (Mueller's) already shared some (material) with the (state) attorney general's office."
He said Mueller, if fired, could potentially share boxes of evidence, and say, "'Do whatever you want with these before I shut off the lights.'"
Allies have advised Trump to avoid fallout by taking steps just short of firing Mueller.
Possibilities include issuing pardons for those facing charges, defunding the probe, or, as suggested by Trump's Canadian friend Conrad Black, shuffling the senior ranks of the Justice Department, and instructing its new leadership to limit Mueller's investigation — restricting the probe to Russia-related matters during the 2016 election.
But every attack avenue has its obstacles.
Defunding requires an act of Congress. Pardoning people could force them to testify in other cases, without being able to claim Fifth Amendment protection against self-incrimination. Several lawyers say it would also build an obstruction of justice case against Trump.
Still, one former Obama White House official agreed firing Mueller isn't the smartest play.
"If I were advising Trump I'd say... 'Two options here to... get Mueller off your back. You can do what you need to do to fire him, which I think would be an extraordinary breach, and would draw a lot of attention, and hey, Donald Trump, you remember (firing James) Comey?... That didn't go well,'" said former Obama aide Jon Lovett on the podcast, "Pod Save America."
"(The other option) I would say, (is), 'Discredit him.'"