Senator Barack Obama has clinched the Democratic presidential nomination, becoming the first African American to lead a major party presidential ticket. On Tuesday, Obama won the Montana primary and secured a last-minute rush of superdelegates, including former President Jimmy Carter. This pushed him over the threshold of needed delegates, ending the longest and most expensive primary campaign in history. Last night, Obama spoke before nearly 20,000 supporters in St. Paul, Minnesota, the site of this year’s Republican National Convention.

Sen. Barack Obama: “America, this is our moment. This is our time, our time to turn the page on the policies of the past, our time to bring new energy and new ideas to the challenges we face, our time to offer a new direction for this country that we love.”

NBC’s political analyst Chuck Todd called Obama’s victory over Senator Hillary Clinton “the greatest political upset maybe in the history of American politics.” Obama is expected to officially accept the Democratic nomination for president on August 28th, the forty-fifth anniversary of Dr. Martin Luther King, Jr.’s “I Have A Dream” speech.