Click here to watch "Responsibility."

Hoping a lucky break could still send the nomination her way, the Hillary Rodham Clinton campaign is pressing on with its ground efforts, promising "a Clinton in South Dakota every day" until the June 3 vote ends the string of Democratic primaries and caucuses that began five months ago. Coinciding with her last week of campaign events, Clinton has released two new ads in the state addressing now-familiar themes of her endgame messaging.

The first, a TV spot called "Responsibility" (subscription), addresses voters' economic anxieties, pledging that Clinton will "end $55 billion dollars in giveaways to corporate special interests, reduce the deficit and protect Social Security." As she has since her narrow win in Indiana, Clinton avoids direct attacks on Barack Obama, saving the vitriol for President Bush, whose policies are sending the economy "into a tailspin," according to the ad's announcer.

While "Responsibility" makes a classic competency pitch to South Dakota voters, Clinton's second ad, a minute-long radio spot, combines similar economic appeals with a call for listeners to prove wrong those who say Obama has all but won the nod. (Clinton took the same tack recently in her West Virginia advertising.) "We can pick a president," an announcer says. "Just because South Dakota comes last in the primaries doesn't mean we shouldn't be heard loud and clear."

While recent polling found Obama enjoying a comfortable lead in the state, Clinton has reason to keep up her ad spending. For a relatively small investment in South Dakota's cheap media markets, she has the chance to eke out extra delegates from the state while continuing to generate earned media. More importantly, Clinton's campaigning maintains pressure on the Obama camp to fight out the last primary contest rather than shift entirely to general-election mode.