Medicaid expansion is a bad idea. It’s also bad politics for potential Republican presidential candidates, as Jim Geraghty explains at National Review Online.

Can a Republican governor expand Medicaid in his state, as part of Obamacare’s implementation, and go on to compete for the GOP presidential nomination in 2016? A new poll suggests the answer is no.

The Foundation for Government Accountability, a free-market think-tank based in Naples, Fla., commissioned a poll of 500 likely voters in each of the first three presidential-selection states — Iowa, New Hampshire, and South Carolina. The results indicate that expanding Medicaid is phenomenally unpopular among Republican voters who intend to participate in the primaries or caucuses in those states, and that any aspiring president who did implement that change would face an uphill battle. …

… In Iowa, an astounding 76.6 percent of self-identified GOP voters said they were “very opposed to Obamacare’s Medicaid expansion,” and another 9.8 percent said they were “somewhat opposed.”

In New Hampshire, 74.7 percent of self-identified GOP voters said they were “very opposed” to the expansion, and another 9.9 percent said they were “somewhat opposed.”

In South Carolina, 73.2 percent of self-identified GOP voters said they were “very opposed,” and 9.4 percent said they were “somewhat opposed.”

One pollster not involved in this survey said he’s usually a bit wary about asking respondents about a relatively obscure policy area like Medicaid, because “inevitably you have to explain something to a respondent who knows nothing or almost nothing about it, then ask them if they support it, within about 15 seconds.” But considering Republican-base voters’ general opposition to additional spending, the results seem in line with expectations.