On a Saturday afternoon in Michigan, with the sky still cloudy from smoke from the Canadian wildfires, hundreds of voters packed the opulent 104-year-old Detroit Opera House, rising from their seats to cheer loudly as Sen. Bernie Sanders and Democratic Rep. Alexandra Ocasio-Cortez took the stage.

As two of the leading figures on the American left, Ocasio-Cortez and Sanders were there to defend Senate hopeful Abdul El-Sayed, a doctor running on a universal healthcare platform.

His supporters carried signs with El-Sayed’s slogan “Medicare for All” and wore T-shirts urging an end to immigration enforcement and American aid to Israel.

But they weren’t the only ones who tuned in.

Voters and politicians across the country are watching to see if El-Sayed can secure the Democratic nomination to run for the Senate in November’s midterm elections. His opponent, Congresswoman Haley Stevens, is an experienced politician with lots of money, thanks in part to large corporate donations to her campaigns.

The two represent the divisions within the Democratic Party as it attempts to regain control of Congress. On one side is the centrist establishment, backed by the traditional power players. On the other is the left wing of the party, exemplified by Sanders and Ocasio-Cortez, as well as New York City Mayor Zohran Mamdani.

But while left-wing Democrats have seen a wave of victories during this summer’s primaries, including in New York and Colorado, what remains to be seen is whether they can win back the support of disillusioned working-class voters, who flocked to President Donald Trump in 2024.

In Michigan, which voted for Democrat Joe Biden in 2020 but for Trump four years later, the open Senate seat is a must-win for Democrats.

The seat had been held by one of their own, and if the party hopes to make progress in the Senate and stop Trump’s agenda, they will have to keep him. Whoever wins the primary on August 4 will compete against Trump ally Mike Rogers on November 3.

At Saturday’s rally, some in the crowd felt hopeful as Ocasio-Cortez promised that El-Sayed represented the “politics of the future.”

But miles away from the scene, other voters were less confident in their ability to defeat Stevens or secure a Democratic victory by touting policies such as health care for all and staunch opposition to Israel’s military campaign in Gaza.

“Maybe this is not the time for progressives,” said Colleen Houlihan, a 74-year-old woman from Ferndale, Michigan, who will likely vote for Stevens. “I want radical change in the country, but we have to start with this administration and there has to be an eligible candidate to return power to sensible hands.”