State of the Union response speeches come with an inherent disadvantage: Your speech has to be written before you know what the president is going to say. Responding to President Donald Trump’s address to a joint session of Congress on Tuesday is likely to be exceptionally difficult, since Trump has a habit of tossing off such an array of bizarre claims that it’s easy to get distracted.

The selection of former Kentucky Gov. Steve Beshear is a sign that Democrats are making a clear choice. Whatever it is that Trump talks about, they are going to talk about health care — about how Republicans want to deregulate the insurance industry and jeopardize insurance that millions of people currently enjoy, while Democrats do not want to do that.

For multiple election cycles, Democrats often seemed reluctant to defend or brag about the signature legislative achievement of the Obama administration. Now that the Affordable Care Act is on the verge of destruction, the party has finally decided that it is a winning issue.

Donald Trump is very hard to respond to

The trouble with coming up with an answer to Trump’s speeches is they don’t deliver much of a coherent message or argument.

Take Trump’s keynote address at the Conservative Political Action Conference. It featured Trump’s bizarre assertion that Paris is now so unsafe that tourists refuse to go there, his equally bizarre assertion that the CEO of TransCanada was surprised that Trump approved the Keystone pipeline, his goofy insistence that Washington Post reporting that led him to fire his own national security advisor was fake news, “lock her up” chants, a mischaracterization of the election outcome, and so much more.

Yet for all the odd moments, the speech did not make any news by the standards of a conventional presidential speech.

With all of Washington waiting to see what Republicans will do — or at least try to do — on health care and tax reform, Trump offered no guidance. He asserted that things are bad, and said he would make them better in an entirely nonspecific way. He also talked about his desire to rework NAFTA, but offered no new ideas on what this should entail. He spoke of future trade bilateral agreements that would be much better, but offered no ideas about what countries these deals will be made with or what their content will be. He called for a military buildup, but didn’t specify an amount of money, an objective, or a financing mechanism.

It was a weird cavalcade of non sequiturs and falsehoods that, on policy, was also completely vacuous.

Beshear has a good story to tell on health care

Beshear isn’t a rising star in the Democratic Party. He’s not one of its federal legislative leaders, he’s not a nationally recognized figure, and he’s not a legendarily skilled orator.

He’s also not a woman, an immigrant, a person of color, or otherwise someone who’ll break new ground or excite the Democratic base on an identity level. But he is a precommitment device to talk about health care, and to do it with a good story to tell.

Kentucky is a bit of an oddball state that’s swung hard to the right in national politics in the 21st century, but had enough lingering strength in its state Democratic Party that Democrats were running the whole show when Affordable Care Act implementation began. Consequently, Kentucky expanded Medicaid and built its own state health insurance exchange — they call it Kynect — and therefore wasn’t impacted by the initial rollout of HealthCare.gov. Combine those two factors with the reality that Kentucky is a poor state, and the results have been a boon.

Kentucky has experienced the largest drop in the share of people who are uninsured in the country. That’s great for newly covered Kentuckians. And the tab for all those new insurance policies is largely paid for by tax hikes on extremely wealthy people nationwide, relatively few of whom live in Kentucky. The result is a huge infusion of money into the state’s economy.

Democrats think they can win on health care

The Affordable Care Act’s benefits for Kentucky didn’t halt the state’s rightward slide. As Vox’s Sarah Kliff found when she reported from the state, it didn’t even stop people who directly benefitted from Obamacare from voting for Trump. Kentuckians came to see the Democratic Party as not for people like them — as fundamentally hostile, on an identity politics level, to working-class white Christians living in a place whose economy has long been defined by natural resource extraction.

But as Kliff also found, Obamacare beneficiaries rationalized their voting for Trump by assuming that his election wouldn’t actually imperil their health care:

Many expressed frustration that Obamacare plans cost way too much, that premiums and deductibles had spiraled out of control. And part of their anger was wrapped up in the idea that other people were getting even better, even cheaper benefits — and those other people did not deserve the help. There was a persistent belief that Trump would fix these problems and make Obamacare work better. I kept hearing informed voters, who had watched the election closely, say they did hear the promise of repeal but simply felt Trump couldn’t repeal a law that had done so much good for them. In fact, some of the people I talked to hope that one of the more divisive pieces of the law — Medicaid expansion — might become even more robust, offering more of the working poor a chance at the same coverage the very poor receive.

As an opposition party, Republicans were able to make enormous hay out of the reality that ACA coverage really does have a lot of flaws and limits. As a governing party, however, they are beginning to wrestle with their reality that all of their various “repeal and replace” plans would leave fewer people covered and greatly reduce the average quality of coverage.

With the public now focused for the first time on the benefits of the Affordable Care Act rather than its shortcomings, its popularity has reached a new record high. The choice of Beshear is a clear indication that Democrats think it makes sense to try to cut through the noise and chaos of Trumpism and focus on this issue.

Democrats passed a law that taxed rich people and regulated big business. That law is helping millions of people. Republicans want to reverse that. That’s not the only thing going on in Donald Trump’s America, but it’s the thing that works as a message in the broadest number of places, and it’s the message Democrats are going with on Tuesday.