"What we have to do is determine who will be the best president and the stronger candidate against Senator McCain," she told a couple hundred residents of the reservation. "I believe I am, and I believe the states I have won and the electoral votes I will win make a very strong argument for that."
To bolster the argument, her campaign sent uncommitted superdelegates a letter, a memo and a compilation of state polling data demonstrating how she would run stronger than Barack Obama - who is closing in on the nomination - in the fall. Among other things, they pointed to her wins in primaries in such swing states as Ohio and West Virginia, and her strong margins among certain voting blocs, such as older women, Hispanics and rural voters.
"I hope you will consider the results of the recent primaries and what they tell us about the mind-set of voters in the key battleground states," Clinton said in the letter. "I hope you will think about the broad and winning coalition of voters I have built."
With the final three primaries here and in Montana and Puerto Rico next week set to award 86 delegates, Clinton trails Obama by nearly 200, making it almost mathematically impossible for her to catch him. But she has been appealing to superdelegates who have yet to declare for a candidate to pick her.
The former first lady and her advisers also have pushed for the Democratic National Committee to seat delegations from disputed primaries in Michigan and Florida at the national convention in August.
Clinton claims to have won the most popular votes, but that includes results from Michigan and Florida, where no delegates were awarded because the DNC had punished both states for breaking party rules by holding primaries before Feb. 5.
But Obama leads Clinton by nearly 450,000 votes in the combined popular vote in primaries and caucuses where delegates were at stake, according to an Associated Press analysis.
So Clinton is investing plenty of time in the final states, including a 2 1/2 drive through the South Dakota Badlands to get to Kyle, population 970.
Earlier in the day, she visited Mount Rushmore, where the faces of four presidents are carved into a mountain. She batted away reporters' questions about whether she or her husband, former President Clinton, might one day be immortalized there.
"Why don't you learn something about the monument?" Clinton said.
