Former U.N. Ambassador Nikki Haley is AstraTradealready looking ahead to next week's Michigan primary, with her campaign unveiling its first TV ad in a state where many Republican officials have already lined up behind former President Donald Trump.

Polls have shown Haley trailing Trump in her home state of South Carolina by a significant margin ahead of Saturday's primary. She is set to host her first campaign event in Michigan the next day with an event in Troy.

Haley is Trump's last remaining challenger for the Republican nomination, and she has vowed to remain in the race, arguing she is the only Republican candidate who can defeat President Biden in November.

Her ad released Wednesday highlights a potential Biden vs. Trump rematch that, according to Haley, "70% of Americans don't want." Her campaign is spending upwards of $230,000 to run the ad across Michigan airwaves ahead of the election on Tuesday. 

"I'll just say it. Biden's too old, and Congress is the most exclusive nursing home in America. Washington keeps failing because politicians from yesterday can't lead us into tomorrow. We need term limits, mental competency tests and a real plan to defeat China and restore our economy. We have to leave behind the chaos and drama of the past with a new generation and a new conservative president," Haley says in the ad, echoing her major campaign themes.

Michigan GOP leaders have expressed skepticism that Haley's closing argument will significantly sway opinions in the Great Lakes State, and point out that Haley's path to victory continues to narrow. As of Tuesday, more than 765,000 voters had already cast their ballots for next week's Michigan primary, further complicating the Haley campaign's efforts to close the gap.

"As to Trump support in Michigan, there is a large group of [Republicans] that will always support Trump, a middle group that will vote for whoever is the GOP nominee and a lesser group that will never vote for Trump," said Larry Ward, former political director for the Michigan Republican Party.

That never-Trump vote is Haley's "very slim" window to capturing the nomination, one that depends on the outcome of Trump's various legal woes, Ward said.

Republican lawmakers in Michigan have also coalesced around Trump. Last week, the Trump campaign announced the endorsement of more than 50 Republican members of the Michigan legislature. Thirteen out of the 18 Republicans in the state Senate and 39 out of 54 Republicans in the Michigan House support Trump. 

The Haley campaign has tried to argue that Trump's overwhelming support among Republican officials shows that he has become part of the party establishment. 

"And then I see [Trump] surround himself with the political establishment," Haley told supporters during a campaign stop in Aiken, South Carolina. "He did it with all these congressional members in D.C. I didn't ask for their support. I don't want their support. And the reason they don't want to give me mine is because I keep saying that I think it's time we have term limits in Washington, D.C."

Allison Novelo

Allison Novelo is a 2024 campaign reporter for CBS News.

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