WASHINGTON (AP) — Abruptly on the spot as the new face of “Obamacare,” Sylvia Mathews Burwell faces steep challenges, both logistical and political.

Burwell, until now White House budget director, was named by President Barack Obama on Friday to replace Health and Human Services Secretary Kathleen Sebelius, who oversaw the messy rollout of the health care overhaul. Now the new secretary must keep the complex program running smoothly and somehow help restore a cooperative dialogue with Republicans who are hoping to use the law’s problems to regain control of the Senate in November.