President-elect Donald Trump has issued warnings to Republican senators who oppose his nominees, suggesting they could face primary challenges, particularly targeting House Republicans who supported a bipartisan spending bill.

This has led to growing concerns among Republican lawmakers about the potential for primary challenges from Trump and his allies against those who diverge from his policies and Cabinet nominations.

In response, incoming Senate GOP Leader John Thune emphasized the party's commitment to supporting incumbents and maintaining unity to leverage their majority effectively.

Senator Lisa Murkowski, who previously faced a Trump-backed challenger, echoed the sentiment that internal threats could undermine the party's cohesiveness.

Senator Mike Rounds condemned the threats against fellow Republicans, labeling them as misguided and harmful to the party's integrity.

Senator Susan Collins, known for her centrist stance and up for reelection in 2026, acknowledged the looming possibility of primary challenges.

Senator Lindsey Graham, a Trump ally, advised his colleagues to vote based on their conscience rather than succumbing to online pressures or threats.

Senator Cynthia Lummis criticized the tactic of threatening primaries, arguing that it often backfires and is detrimental to party unity.

Senator Joni Ernst has faced personal attacks for her hesitations regarding Trump's defense secretary nominee, highlighting the intense scrutiny Republican lawmakers encounter.

Senator Bill Cassidy, who voted to convict Trump during his impeachment trial, is currently facing a primary challenge from Louisiana Treasurer John Fleming, illustrating Trump's significant influence over Republican nominations.

Adding to the tension, Elon Musk, a close associate of Trump, announced plans to financially support primary challengers against Republicans who oppose Trump.