O’Rourke’s supporters view the criticism from progressives as limited, and his colleagues have said privately that it does not bother him. But in a through-the-looking-glass experience, supporters of O’Rourke have been pressed to reiterate the progressive credentials of a Democrat who, in his Senate campaign, was chiefly criticized for being too progressive and not diluting his positions to account for the state’s conservative tint. They point to his support for Medicare for All and for leftist drug, military and immigration policies. And they were buoyed by the release of a straw poll by the progressive advocacy group MoveOn this week that put O’Rourke first in a field of potential 2020 candidates.

In response to a constituent on Friday, O’Rourke reiterated his support for background checks and a ban on the sale of assault-style weapons. And he pushed back against criticism that he took money from employees of oil companies in a race in which he raised more than $70 million from a national network of mostly small donors.

He said it is “really important to remember we did not receive a single PAC contribution” and that the campaign took money from employees of a range of industries, including the “cosmetology industry, the telecommunications industry, the cupcake baking industry.”