North American Politics Headlines at 1:48 p.m. EDT

At White House, insurers again pledge no-cost virus tests

Stakes rise for Sanders heading into Michigan primary

6 questions heading into next set of Democratic primaries

Edited Biden video portends social media challenges in 2020

Melania Trump cancels fundraiser, cites scheduling conflict

Trump says sexism not to blame for end of Warren's campaign

One more victory: Biden wins most Super Tuesday delegates

Trump's CDC visit turns into scattershot defense on virus

Deval Patrick becomes latest former 2020 rival to back Biden

New qualifications for next debate likely rule out Gabbard