Joe Biden has been president of the United States for 174 days. On at least 21 of those days, about 1 in every 8, he has talked about the threat posed by autocracy. Often, as he did Tuesday in Philadelphia, he has warned about the risk of an ascendant autocratic movement in the United States, one fomented by his predecessor — and one that many in his own party seem to be underestimating.

Biden’s speech was broadly focused on protecting voting rights. He spoke about the need to ensure that Americans had both the right and access to vote, the latter of which has become a focal point of much of his party in the face of widespread Republican efforts to restrict it. But he also spoke about the threat that bubbled up in the wake of last year’s presidential election, that some political leaders — encouraged then by Donald Trump — felt empowered to undo the results of the popular vote in an effort to grant Trump a second term in office.

“It’s no longer just about who gets to vote or making it easier for eligible voters to vote,” Biden said. “It’s about who gets to count the vote. Who gets to count whether or not your vote counted at all. It’s about moving from independent election administrators who work for the people to polarized state legislatures and partisan actors who work for political parties.”

Republicans, Biden said, “want the ability to reject the final count and ignore the will of the people if their preferred candidate loses.” That’s a reference to aspects of several proposed laws in which legislators moved to reinforce state legislatures’ primacy over determining how to allocate presidential electors.

“We must ask those who represent us at the federal, state and local levels: Will you deny the will of the people? Will you ignore their voices?” Biden continued. “We have to ask, are you on the side of truth or lies, fact or fiction, justice or injustice, democracy or autocracy? That’s what it’s coming down to.”

Biden has often offered this democracy vs. autocracy framework in the context of international relations, pitting a free United States against, say, an ascendant China. But here, he was echoing the large number of voices, including many prominent political scientists, who are concerned that the United States is seeing an erosion of its own political freedoms — a warning Biden also offered in his speech to Congress earlier this year.

A poll released by Marist University last month, conducted for NPR and PBS NewsHour, reveals a striking challenge Biden faces in making that case. Two-thirds of Americans believe that democracy is, in fact, under threat in the United States. But far more Republicans do than Democrats — and that’s especially true of Trump supporters.

Among Trump supporters, nearly 9 in 10 think democracy is under threat. Among Democrats, only 6 in 10 do.

This, by itself, is a political challenge for the president. He needs Democratic enthusiasm and activism to push Congress to act on election defense. But it’s a bigger problem because those Republicans who view democracy as being under threat are more vocal and pulling in exactly the opposite direction.

It’s clearly the case that those Republicans do not see democracy as being under threat because Republican officials want more options to undo election outcomes they don’t like. In fact, many Republicans would probably support such a shift, given the broad and erroneous belief that the 2020 election was tainted by rampant election fraud. There remains no credible evidence of even small-scale systemic fraud and certainly not enough to have affected the final electoral-vote count (much less the popular vote).

But because Trump has been so effective at convincing his base that fraud occurred, many Republicans see democracy as imperiled. Not by efforts to scale back the voice of voters, as Biden fears, but because they think without evidence that the voice heard in 2020 was inauthentic or fraudulent.

Biden explicitly called out Trump’s “big lie” about election fraud, though, of course, few of the president’s supporters actually believe it. Biden’s challenge is instead making Democrats feel the same concern he feels about how the rules are being shifted against their party not just before polls close, but after. Most Democrats do see democracy as imperiled, but a third think it’s alive and well, perhaps convinced by Biden’s victory itself.

The president also spoke of building a coalition in defense of democracy, a coalition that includes Democrats and Republicans.

“We’ll be asking my Republican friends in Congress and states and cities and counties to stand up, for God’s sake, and help prevent this concerted effort to undermine our election and the sacred right to vote,” Biden said near the end of his speech, his voice rising. “Have you no shame? Whether it’s stopping foreign interference in our elections or the spread of disinformation from within, we have to work together.”

If the Trump era has taught us anything, it’s that few Republicans are likely to volunteer.