Ruben Gallego's Senate bid sets up a potential battlefield in Arizona, with fmr. Rep. Ron Barber

<p>Rep. Ruben Gallego's (D-Ariz.) Monday launch of his 2024 Senate bid could signal the first major challenge to Sen. Kyrsten Sinema (I-Ariz.), who hasn't announced re-election plans, but shocked Democrats in her switch to independent, late last year. Former Rep. Ron Barber (D-Ariz.) joins Chuck to detail how the Grand Canyon state foreshadows the changing face of party politics nationally.</p>