In an extensive article posted on X Monday night, Democratic Michigan Rep. Haley Stevens laid out her reasoning for endorsing Republican Mike Rogers and condemned the reactions from those in her party.

Stevens' surprise endorsement came after months of tension between her and the Democratic Michigan Senate candidate Abdul El-Sayed since he defeated her in the primary in August by 1 percentage point.

Though they appeared together in the initial days after the primary, Stevens never appeared with El-Sayed on the trail.

She said that her experience of feeling dismissed by El-Sayed in the time after the primary led her to question his ability to serve, "That experience raised a bigger question. If a candidate cannot make room for people who supported his primary opponent, how will he represent an entire state filled with people who disagree with him?"

She criticized the narrative that her fiancé, Jason Turkish, had motivated the decision. "That is sexism dressed up as political analysis. My fiancé has his own views. I have mine. I made this decision, and I am proud of it," she wrote.

She criticized the reaction of Democrats to her endorsement, saying, "We cannot preach inclusion while punishing dissent. We cannot promise to heal a divided country if we cannot tolerate disagreement among ourselves. And we cannot build a lasting majority by making Americans feel their concerns are unwelcome."

She ended by saying she plans to "lead an effort' to "build a stronger, more welcoming, more courageous Democratic Party."

-ABC News' Diana Paulsen

While the featured celebrity at tonight's Abdul El Sayed event was the rapper Common, the biggest surprise speaker of the night was El-Sayed's wife, Dr. Sarah Jukkaku.

She has not appeared often on the campaign trail with him and this is her first time speaking at one of his events.

Introducing him at his final rally in Detroit on Election Eve, she told stories of their college courtship and presented him as honest and straightforward, saying of him, "What you see is what you get."

"Abdul is the same to me and my daughters as he is to you. He says the same things no matter where he is and no matter who he's talking to because he believes and means those things, and that's what makes him such an unusual politician," Jukaku said.

"No corporation, no billionaire, no special interest. No one tells him what to do or what to say -- except maybe me sometimes. But really, he carries himself with a sincerity and an earnestness that our politics so desperately lack and so desperately need right now," she added.

The National Guard will have a limited role in Tuesday’s elections, with a handful of states deploying small teams of troops for cybersecurity support, as it has done for years, and one relatively unusual mission in Washington state that will put Guardsmen near ballot drop boxes.

Washington Gov. Bob Ferguson, a Democrat, is mobilizing roughly 100 unarmed Guardsmen in civilian clothing to monitor ballot drop box locations, following a 2024 incident in which a ballot box was burned in the state and hundreds of ballots were destroyed.

“These individuals would not interact with voters or have a conspicuous presence at voting locations, but would be available to immediately coordinate with local authorities should issues arise,” Brionna Aho, a spokesperson for Ferguson, told ABC.

In Washington, D.C., where roughly 3,000 Guardsmen remain deployed as part of President Donald Trump’s security mission, troops are explicitly barred from approaching any voting sites.

Photos recently circulated on social media showing Guardsmen standing near ballot boxes, raising concerns about their proximity to election infrastructure. But two officials familiar with the situation said the troops had simply lingered in areas where ballot boxes happened to be located, rather than deliberately positioning themselves near them. Both officials said troops are not supposed to be there, and that ballot box locations are marked in their GPS systems they use to navigate the city, with geofencing restrictions intended to keep them away.

Elsewhere, several states, including North Carolina, Iowa, Arizona and Florida are deploying smaller teams of roughly a dozen to two dozen Guardsmen each to support cybersecurity operations, monitoring potential threats to election systems.

-ABC News' Steve Beynon and Catherine Bouvet

The Supreme Court late Monday afternoon denied the Trump administration's request for an injunction ordering California to segregate 20,000 ballots that it said could have been cast by noncitizens.

The court did not explain its decision. There were no noted dissents.

The move effectively shuts down the president's legal battle in California over alleged noncitizen voting. Once the ballots in question are opened and processed they will no longer be retrievable for future analysis.

State officials have said a large percentage of a select sample of the list presented to them included U.S. citizens. The administration did not explain how it derived the list or what basis it had to suggest all of the names were likely unlawful voters.

-ABC News’ Devin Dwyer

An analysis of Federal Election Commission data by campaign finance tracker, OpenSecrets projects that spending on the 2025-2026 election cycle will reach about $12 billion -- meaning that, at the federal level, this cycle is slated to be the most expensive midterm election on record.

An analysis by AdImpact that incorporated gubernatorial elections found it to be the most expensive cycle on record, surpassing even the 2023-2024 general election cycle.

Advertising spending across House, Senate and gubernatorial races this cycle cost about $7.1 billion, according to an analysis by the Wesleyan Media Project. About $1.4 billion of that ad spending occurred late in the cycle, between Oct. 12 and Oct. 25.

-ABC News' Will Lennon