Why is that important? The revelation confirms the geopolitical context in which Russian President Vladimir Putin decided to place his chips on a major new influence campaign against the West. In 2014, he was angry at what he perceived as American meddling in Ukraine, in his own front yard. A scheme from that year in which Russia leaked a wiretapped phone conversation with an American diplomat has proven to be its own little preview of 2016.
Placing the origins of the Russian effort that far back in time also raises new questions about what President Obama's administration knew about what was happening. Were they aware? Did Obama and his aides look the other way from Russia's actions in order to protect other aspects of the relationship such as the international deal to restrict Iran's nuclear program?
2. Russians didn't just post from afar. They traveled to the U.S.
At least three Russian operatives physically traveled to the United States to do reconnaissance for their active measures campaign, according to the indictment.
They traveled throughout the West, South and Midwest, to New York and elsewhere. That led to the tracking and study of American political organizations that later matured into the sophisticated targeting of certain groups during the 2016 election cycle. For example, black voters later were encouraged not to vote for Hillary Clinton by messages suggesting they not vote at all or that they vote for a third-party candidate. Anti-Muslim groups were encouraged to stage rallies and so on.
Russian operatives also bought space on computer servers within the United States. That enabled them to connect from their headquarters in St. Petersburg and, using a virtual private network, post on Facebook and Twitter while appearing to be inside the United States.
The fact of the travel of Russian operatives also raises questions about other aspects of the influence campaign. How many meetings might have taken place between intelligence officers or their agents and American political organizations that might have been infiltrated, for example?
And will stories about Russian spies actually prowling around the U.S. — not just posting from behind a firewall somewhere overseas — change the politics of punishing Russia for its interference? Trump has been criticized for not imposing stronger sanctions after they were put into law last year by Congress.
3. Operatives dealt directly with Americans, including some Trump campaign workers
Russian influence-mongers corresponded with a number of Trump campaign workers and even paid some Americans to show up for protests they organized, the indictment alleges. They hired a person to buy a cage and paid another to stand in it pretending to be Hillary Clinton — part of the push to "lock her up."
Mueller's indictment says none of the Americans knew they were dealing with Russian operatives, but they nonetheless provided the Russians with some important help.
For example, in June of 2016, Russian operatives began talking with an American "affiliated with a Texas-based grassroots organization. During the exchange [the Russians] learned ... that they should focus their activities on 'purple states like Colorado, Virginia and Florida.'"
This insight, which might appear obvious to Americans, was treated as a major gem by the Russian influence operatives. Remember, these were foreigners trying to understand how to target a foreign land. It also helps explain another avenue through which they tried to influence the presidential race: cyberattacks on state elections systems.
The Russians might have wanted to know, simply, what those systems were, what information they contained and how they might have been able to exploit them. As outsiders they might not have known or trusted that a lot of voter information was already public in lists bought and sold by political campaign professionals.
4. Trump now acknowledges active measures
President Trump has gone back and forth about what he accepts and what he rejects about the Russian active measures campaign. On a trip to Asia, the president said he believed Putin believed there was no election interference.
The indictment on Friday, complete with an on-camera announcement by Deputy Attorney General Rod Rosenstein, took away much of Trump's room to maneuver. So the president conceded the fact of the attack while modifying his position again.