WASHINGTON — You might call North Dakota the antithesis of President Obama’s political base.

Whites make up 90 percent of its population, which is fewer than one million people and mostly in rural areas. Its proportion of people 65 and over exceeds the national average. There was never a chance that North Dakota would give Mr. Obama its three electoral votes.

So Mr. Obama has not given North Dakota his time. It is one of six states he has not visited as president, along with South Dakota, Arkansas, Idaho, South Carolina and Utah. He has gone just once to Kansas, Kentucky, Mississippi, Montana, Nebraska, Tennessee and Wyoming.

Mr. Obama’s near-complete absence from more than 25 percent of the states, from which he is politically estranged, is no surprise, reflecting routine cost-benefit calculations of the modern presidency. But in a country splintered by partisanship and race, it may have consequences.

America’s 21st-century politics, as underscored by the immigration debate embroiling Congress, increasingly pits the preferences of a dwindling, Republican-leaning white majority against those of expanding, Democratic-leaning Hispanic and black minorities. Even some sympathetic observers fault Mr. Obama as not doing all he could to pull disparate elements of society closer. “Every president should make an attempt to bridge the divide,” said Donna Brazile, an African-American Democratic strategist. “It’s a tall order. I wouldn’t give him high marks.”