The legislation for Trump's agenda on taxes, health care, immigration, energy and more would add $3.3 trillion to the deficit over a decade, according to the Congressional Budget Office.
The president accuses Selzer of fraud after she conducted a poll right before the 2024 election that showed Kamala Harris leading in Iowa. He ended up winning the state.
The decision further undermines people's ability to sue federal officials for constitutional violations, which the Supreme Court first recognized in 1971.
A group of unions — another key Democratic constituency — is launching a separate summer organizing effort that will target states President Donald Trump won in the last election.
The court will consider a Republican request to strike down restrictions on how much national party committees can spend in coordination with individual campaigns.