As the presidential caucuses in Iowa loom, the Democratic frontrunners are ratcheting up the rhetoric with a flurry of ad campaigns and trading barbs with increasing snark and snarl.

Yesterday, Hillary Clinton appealed to Iowa voters with a new ad titled "This House." The 60-second spot outlines Clinton's case to be the next occupant of the White House, highlighting her political bona fides as a former first lady, U.S. senator and secretary of state. It also carried a not-so-subtle undercurrent of portentous gravity. It isn't quite on par with, say, the America-as-post-apocalyptic-immigrant-infested-hellscape portrayed in Republican candidate Donald Trump's pants-igniting first TV ad. But it's not exactly warm and fuzzy, either.

Today, Clinton rival Sen. Bernie Sanders (I-Vt.) took a decidedly different tack with a new ad of his own. Set to the inspirational folk-rock strains of the Simon & Garfunkel classic "America," Sanders' ad appeals to a spirit of hope and unity in both tone and scope.

The ad sets the scene with images of Rockwellian small towns, tugboats in a quiet harbor, farmers with cows and young folks working. As Paul and Art gently croon, we see a smiling Sanders shaking hands on the campaign trail, greeting fans with his wife and riling up enormous crowds at rallies — including his campaign kickoff on the Burlington waterfront.

Then, at the song's hooky climax, "They've all come to look for America," the faces of thousands of Sanders supporters cascade across the screen — images his campaign donors submitted digitally. We hear not a peep from the man himself until the very end, when, over an image of the grinning candidate at a rally podium he approves the ad and… Ah jeez, I think I've got something in my eye. Just watch it: