Ruben Gallego starts TV advertisements as the Arizona US Senate election unfolds without Sinema.

Phoenix — As the key Arizona election becomes a one-on-one struggle after incumbent Kyrsten Sinema declined to run again, Democratic Rep. Ruben Gallego began airing his first television advertising on Tuesday. Gallego's ad describes him as a U.S. Marine who lost 48 men in tough Iraqi warfare.

Arizona is one of several Senate races that will decide power. It is intensifying after Sinema, a former Democrat, said she would not run as an independent, allowing Democrats to support Gallego

Gallego is highlighting his military history and humble origins to rise beyond his safe Democratic Phoenix seat since 2015.

Gallego claims in his ad that he attended Harvard University without money or connections after working as a cook and janitor. He also mentions his PTSD after returning from Iraq, claiming he “survived the memories of war so I can be a good dad.”

The video does not name Republican frontrunner Kari Lake, who is well known after nearly three decades as a Phoenix local news anchor. A staunch Trump supporter

 she's gained a national presence among Republicans despite her loss in last year's Arizona governor's election, which she continues to challenge.

Lake ran her own commercial during the Iowa caucuses and New Hampshire primaries in January. Depending on the White House party after November, Republicans need a net gain of one or two seats to control the Senate.

Republicans have long dominated Arizona, but Sinema's 2018 win signaled a Democratic surge. With a combination of right-leaning Republican voters who loathe Trump, they've won three Senate elections and the state's top three posts.

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