With zeal, excitement and a meticulous attention to detail, the administration of Gov. Mark Dayton is trying to expand health insurance coverage and remake Minnesota's insurance market along the lines envisioned by President Obama. But one notable group has been missing from the process: Republicans, who control both houses of the State Legislature. Mr. Dayton, a Democrat, and the Republicans find themselves in an icy standoff. The situation is a case study of the politics found in state capitols around the country as officials grapple with a crucial element of the new federal healthcare law.