Hi. Welcome to On Politics, your guide to the day in national politics. I’m Nick Corasaniti, back in the seat as your host on Tuesdays for our coverage of all things media and messaging.

Sign up here to get On Politics in your inbox every weekday.

The presidential campaign has largely shifted to the recesses of public consciousness during the coronavirus outbreak. So, too, has political broadcast advertising: Since last Tuesday, Joe Biden, Bernie Sanders and President Trump haven’t aired a single ad on television.

It’s a difficult time for political campaigns to run paid messaging. Calls for unity to stop the pandemic are widespread, and candidates could be accused of politicizing a crisis if they put out attack ads.

But campaign rallies have been canceled, fund-raisers have been called off and in-person canvassing has been halted, all while Americans are spending more time indoors. With Mr. Trump on television constantly, Democratic strategists are worried that his unabated free airtime, even amid a crippling national crisis, gives him a messaging advantage.

In that vacuum, two Democratic groups have started multimillion-dollar advertising campaigns attacking Mr. Trump for his previous comments that played down the threat of the virus.

Priorities USA, one of the major Democratic super PACs, on Monday began a $6 million television and digital advertising campaign in four general election swing states — Florida, Michigan, Pennsylvania and Wisconsin — with multiple ads either criticizing Mr. Trump or trumpeting the record of Mr. Biden.

In one particularly stark ad, a line tracing the exponential growth of coronavirus cases in the United States creeps across the screen, as Mr. Trump can be heard saying, “We have it totally under control” and “One day, it’s like a miracle, it will disappear.” (Those quotations came from January and February; Mr. Trump has since tried to rewrite history by claiming he knew the virus would be a pandemic all along.)

The ad supporting Mr. Biden, which features the candidate proclaiming he would be “better prepared,” is the first such spot from Priorities USA, which had stayed neutral for most of the Democratic primary race but has since declared that it views Mr. Biden as the presumptive nominee.

Pacronym, a progressive super PAC, is in the middle of a $2.5 million digital ad campaign attacking Mr. Trump for his response to the coronavirus. That campaign began in mid-March and will run through the end of April, and the group said it planned to spend at least $5 million in total on digital ads by July.

The ads — which are running in Arizona as well as the same four states Priorities is targeting — are appearing on Facebook, YouTube, Hulu and other digital platforms, and feature a wide array of criticism.

The most recent one highlights criticism from Tucker Carlson, the Fox News host and frequent Trump booster, who has blamed “government incompetence” for a lack of preparedness for the pandemic in the United States.

“When voters consider who they want to be their next commander in chief, they’ll remember how the president’s chaotic administration, negligence and reckless behavior put our lives and economy at risk,” said Tara McGowan, Pacronym’s founder. “Pacronym will continue to make this case to voters online and reach them with facts about how this president is putting us all in harm’s way.”

Another Democratic super PAC, American Bridge, has started including coronavirus ads as part of an $850,000 digital ad campaign attacking Mr. Trump in Wisconsin, Pennsylvania and Michigan. On Facebook, where the group has spent nearly $86,000 in the past week, it is running multiple ads claiming Mr. Trump has “put American lives at risk” and calling out his past comments on the virus.

While it hasn’t put the same kind of money behind ads as Pacronym or Priorities USA, the Biden campaign has started to buy digital ads denouncing Mr. Trump and his approach to the outbreak.

In a Facebook ad shown to Wisconsin voters on Sunday, the Biden campaign ran a 90-second side-by-side comparison of Mr. Trump and Mr. Biden answering similar questions about the virus — choosing clips that showed Mr. Trump lashing out at reporters and Mr. Biden calmly delivering advice from the debate stage.

Mr. Trump, in his televised briefings and on Twitter, has repeatedly claimed that his administration has taken the virus seriously for months, pointing to his decision in late January to restrict travel from China, despite his many remarks minimizing the threat.

The Trump campaign, for its part, has been running a digital ad campaign from an almost parallel universe unaffected by the coronavirus, pitching a “gold card” for donors and selling campaign merchandise like “the EXCLUSIVE Trump Pence Keep America Great Dog Collar.”

Drop us a line!

We want to hear from our readers. Have a question? We’ll try to answer it. Have a comment? We’re all ears. Email us at onpolitics@nytimes.com.

… Seriously

Sometimes, the best messaging is a blunt object rather than a sharp tool. Mayors across Italy, frustrated with those who won’t stay home during the crisis, have been growing more direct in their instructions to constituents, as you can see in this video. (It includes some expletives.)

Thanks for reading. On Politics is your guide to the political news cycle, delivering clarity from the chaos.

On Politics is also available as a newsletter. Sign up here to get it delivered to your inbox.

Is there anything you think we’re missing? Anything you want to see more of? We’d love to hear from you. Email us at onpolitics@nytimes.com.