Who is Kyrsten Sinema? Friends and foes ponder an Arizona Senate enigma

Democrat's commitment to bipartisanship and reluctance to explain position on Biden spending plans contribute to mounting frustrations - and a possible primary challenge

Moments after the Senate voted in an unusually bipartisan way to advance a $1tn infrastructure deal, Kyrsten Sinema hobbled on a broken foot to a press conference to mark the occasion. At the podium, the Arizona Democrat was greeted by Rob Portman, a Republican from Ohio with whom she had led negotiations over how to repair ageing roads and bridges and broadband networks.

You go first," Sinema whispered.