"Not clapping for our seniors getting the Social Security payments they need? Or the affordable healthcare that could save their lives? Sinema’s silence speaks louder than words," Gallego said.
But Sinema can be seen on video clapping after Biden called for Congress to cap the cost of insulin for everyone at $35 a month and allow Medicare to negotiate drug prices. Politico reporter Sarah Ferris noted that Sinema was not standing, which prompted Gallego to tweet, "tell me you're bought by big pharma without telling me you're bought by big pharma."
Sen. Kyrsten Sinema applauds during President Biden's State of the Union address at the U.S. Capitol on Feb. 7, 2023. (Win McNamee/Getty Images)
Rep. Ruben Gallego speaks to supporters at an election night watch party on Nov. 8, 2022, in Phoenix. (Christian Petersen/Getty Images)
Gallego, a progressive Democrat, launched a campaign to unseat Sinema in the 2024 election in January, after hinting for months that he would challenge her in a primary.
Sinema shocked political observers by switching her party registration from Democratic to independent on Dec. 9, citing increasingly partisan interests and radicalization in both parties in an op-ed for the Arizona Republic.
Rep. Ruben Gallego and Sen. Kyrsten Sinema (Getty Images)
Her move infuriated progressives, although far-left Democrats were already furious with Sinema for refusing to toe the party line on Biden's Build Back Better agenda. Sinema and Sen. Joe Manchin, D-W.Va., blocked the $1.75 trillion spending bill in the Senate, forcing Democrats to compromise and pass a watered-down version in the Inflation Reduction Act, which she voted for.
Gallego has previously accused Sinema of "putting her own interests ahead of getting things done for Arizonans."
Fox News' Houston Keene contributed to this report.