DES MOINES, Iowa — For months, the tumultuous Republican presidential primary has masked a brewing debate among Democrats about their own party’s future.

Now, with Vermont Sen. Bernie Sanders chipping away at Hillary Clinton’s grip on the Democratic nomination, the differences are spilling out into the open as the candidates campaign across snow-covered Iowa.

At its core, the divide between Clinton and Sanders is about just how much to change current economic, health care and education systems, and what the federal government’s role in those areas should be. The candidates often share the same goals, but have different policy prescriptions and preferred tactics for achieving them.

Sanders, an independent who caucuses with Democrats on Capitol Hill, has been unabashed in his calls for a “political revolution,” energizing his crowds as he urges them to join him in leading the country in a “new direction.” Reflecting the views of liberal Democrats, he sees the government as a vehicle that supplies Americans with the basic tools they need to achieve economic security.

If health care coverage is one of those rights, Sanders believes the government should provide it through a single-payer system, even if that means raising taxes. If higher education is now a requirement for jobs in a modern economy, Sanders says the government must guarantee free tuition at public colleges and universities.

Sanders touted his education plan this week through the prism of a young person who may be seeking to become the first in their family to go to college.