A political action committee affiliated with digital progressive group ACRONYM announced Monday that it would launch a $75 million digital advertising campaign to take on President Trump.

Why it matters: Republicans and Trump have kept the digital edge they seized in 2016, which has put Democrats on notice.

Details: The campaign, called "Four is Enough" plans to spend the bulk of its cash on digital ads between now and election day, with a large amount before the primary, according to a statement.

The campaign is led by a political action committee called PACRONYM that's led by ACRONYM CEO and founder Tara McGowan. It will be advised by David Plouffe, former campaign manager of former President Obama’s 2008 presidential campaign.

The ad spend will be focused on major platforms, like Facebook, Instagram, and Youtube, as well as digital TV and audio platforms like Hulu and Pandora.

States that will be targeted include Arizona, Wisconsin, Michigan, Pennsylvania, and North Carolina.

The big picture: The Trump campaign to-date has far outspent his Democratic counterparts on digital ads. In total, the Trump campaign has spent more on digital ads than the top five Democratic contenders combined.

Expand chart Adapted from a Bully Pulpit interactive chart; Chart: Axios Visuals

Yes, but: Some Democratic candidates and outside groups are beginning to pour more money into Facebook, to counter the heavy Republican spend on the platform.

Tom Steyer and Pete Buttiegieg have both outspent the Trump campaign on Facebook in the past two weeks, for example.

And Democratic outside groups like Priorities USA, Steyer's Need to Impeach campaign and Planned Parenthood have collectively outspent most Republican outside groups on the platform since January.

The bottom line: "Democrats have been slow to evolve their strategies to meet the demand for online information," says Tara McGowan, founder of PACRONYM and ACRONYM, in a statement. "This is a DEFCON 1 situation," says Plouffe.

What's next: The group is accepting donations to help build campaign through the Democrats' sophisticated small-dollar fundraising platform, ActBlue. Despite being outspent by Republicans this cycle, they have maintained a strong digital fundraising presence through ActBlue.

Go deeper: Trump is maintaining his digital lead in the 2020 campaign