Former Secretary of State Hillary Clinton on Monday warned that everyone should care about the role of social media in elections ahead of the 2018 midterm elections, after a Trump campaign staffer touted the success of Trump’s digital marketing on social media.

“We should all care about how social media platforms play a part in our democratic process,” Clinton tweeted Monday night. “Because unless it’s addressed it will happen again. The midterms are in 8 months. We owe it to our democracy to get this right, and fast.”

The tweet was in response to a Twitter user who said she was shocked a tweet from Brad Parscale, the Trump campaign’s digital media director, had not gone viral after he estimated the Trump campaign had dramatically more successful CPM, or cost per thousand views, on advertisements than the Clinton campaign.

The exchange on Twitter comes after special counsel Robert Mueller’s office revealed earlier this month that 13 Russian nationals were indicted on charges of conspiracy to defraud the U.S.

Additionally, three defendants were charged with conspiracy to commit wire fraud, and five were charged with aggravated identity theft.

Deputy Attorney General Rod Rosenstein, who is overseeing Mueller’s probe, announced earlier this month that the meddling started in May 2014 and that the Russian groups created posts, ads, and organized events on social media platforms by using names of Americans and other entities.

The ads primarily were primarily opposed to Democratic nominee Hillary Clinton, but at times were against President Trump. The indictment also said it does not suggest members of Trump’s campaign were wittingly involved with the scheme.

Mueller is investigating if collusion between the Trump campaign and the Kremlin occurred during the 2016 election.