'It's astounding': Veteran Senate staffer explains why Kyrsten Sinema is ‘absolutely failing Politics 101’
Sen. Kyrsten Sinema (D-AZ) Screengrab.

Sen. Kyrsten Sinema (D-AZ) is alienating voters and infuriating fellow Democrats by undermining President Joe Biden's agenda -- so what is she doing?

Polling released this week shows the Arizona Democrat is highly vulnerable to a handful of likely primary challengers as voters grow frustrated by her holding up a $3.5 trillion social policy and climate change bill, and a former top staffer to Senate majority leader Harry Reid told The Daily Beast's "New Abnormal" podcast that Sinema was flunking a basic test.

"This is her just absolutely failing to do Politics 101," said Adam Jentleson, who previously served as Reid's deputy chief of staff. "Her constituents say they can't reach her. There's another story out saying all of her allies, people who supported her in her election, haven't spoken to her in a year, and here she is popping up in Europe doing fundraising. This is not good politics, not just from a lefty perspective. This is just basic Politics 101 stuff that she is just completely failing at."

Jentleson said all she has to do is back the Democratic president's agenda, as Sen. Mark Kelly, also an Arizona Democrat, has been doing.

"Nobody's asking her to support Medicare for all," Jentleson said. "Nothing she's doing really makes much sense. There are new polls out showing that her numbers are just absolutely abysmal. She's begging for a primary challenge… I don't think I've seen numbers like this for an incoming senator. I don't think even Joe Lieberman, who drove Democrats crazy, had numbers that bad. It's astounding."