Governors across the political spectrum are hitting a roadblock in their bids to expand Medicaid with federal funds: Republican legislators who adamantly oppose “Obamacare.”

MIT economist Jonathan Gruber — an adviser on the president’s health care law — told Congress on Tuesday he was glib and “inexcusably arrogant” when he said it was “the stupidity of the American voter” that led to the law’s passage. Democrats tried to limit the damage as the GOP raked Gruber at a four-hour hearing, but they acknowledged he has given Republicans a political gift “wrapped in a bow.”

Now that their party has seized the Senate and faces the pressure of governing, an ambitious group of first-term Republicans may try to use that new majority status, and the opportunities it brings, as a springboard to the presidency in 2016.

New Republican senators who sometimes breathed tea-party fire as candidates are adopting a more moderate tone as they enter Congress.

Republican control of the House and Senate seems tantalizingly close, so leading Republicans are turning to a matter often overlooked in campaigns: how to actually govern.