Even before the first ballots were cast in today's Kentucky and Oregon primaries, Hillary Rodham Clinton was already pressing on into new territory, releasing her first ad of the campaign in South Dakota -- one of the two last states to vote in the Democratic contest.

But if the market was new, the ad was not. Called "Falling Through" (subscription), it has been a staple of the Clinton campaign's ad lineup since it first aired in South Carolina four months ago. The spot compares "the Bush economy" to a trapdoor for middle-class families and promises that Clinton could be an able steward of the economy. Like the rest of Clinton's advertising since the Indiana and North Carolina primaries, it eschews attacks on Barack Obama in favor of promises to help working Americans.

As she has in so many recent primary contests, Clinton plans to keep the focus on economic concerns in her advertising and campaign stops in South Dakota, according to campaign spokesman Brendan Gilfillan. "She touched on it in her first rally when she came to Sioux Falls, and about the rural economy in her second stop," he said. "It's an important theme here in South Dakota."

And despite increased pressure for Clinton to exit the race, all signs point to her continuing the campaign until South Dakota and Montana cast the final ballots of the primary: Clinton's camp today released her "South Dakota Native-American agenda" and announced she would be returning for another visit to the state on Friday. "We've had a couple visits from Senator Clinton and a couple from President Clinton," Gilfillan said. "It's going to be full speed ahead in South Dakota."