WASHINGTON ( CNN ) -- In what he called a `` defining moment for our nation , '' Sen. Barack Obama on Tuesday became the first African-American to head the ticket of a major political party . Sen. Barack Obama on Tuesday told supporters he will be the Democratic nominee . Obama 's steady stream of superdelegate endorsements , combined with the delegates he received from Tuesday 's primaries , put him past the 2,118 threshold , CNN projects . `` Tonight we mark the end of one historic journey with the beginning of another -- a journey that will bring a new and better day to America , '' he said . `` Tonight , I can stand before you and say that I will be the Democratic nominee for president of the United States . '' Watch Obama say he 'll be the nominee » . Obama 's rally was at the Xcel Energy Center in St. Paul , Minnesota -- the same arena which will house the 2008 Republican National Convention in September . Speaking in New York , Sen. Hillary Clinton , congratulated Obama for his campaign , but she did not concede the race nor discuss the possibility of running as vice president . `` This has been a long campaign , and I will be making no decisions tonight , '' she said . Watch Clinton congratulate Obama » . There were reports earlier in the day that she would concede , but her campaign said she was `` absolutely not '' prepared to do so . Two New York lawmakers also told CNN on Tuesday that during a conference call Clinton expressed willingness to serve as Obama 's running mate in November . Watch the latest on a possible joint ticket » ' One source told CNN that Clinton told those on the call that if asked by Obama , she would be interested in serving as his running mate . One of the lawmakers said Clinton 's husband , former President Bill Clinton , has been pushing the idea privately for several weeks . The Clinton campaign maintains the New York senator merely said she would do whatever is in the party 's best interest , and that her comments Tuesday are no different than what she has been saying for weeks . Clinton said she would meet with supporters and party leaders in the coming days to determine her next steps . She also asked people to go to her Web site to `` share your thoughts with me and help in any way that you can . '' Watch what could be in store in Clinton 's future » . CNN has projected that Clinton will win the primary in South Dakota and Obama will take Montana . Those states marked the final contests in the primary season . Obama praised Clinton 's campaign . He has been speaking favorably of the New York senator as his focus has turned toward the general election and his battle against John McCain , the presumptive GOP presidential nominee . `` Sen. Hillary Clinton has made history in this campaign not just because she 's a woman who has done what no woman has done before , but because she 's a leader who inspires millions of Americans with her strength , her courage , and her commitment to the causes that brought us here tonight , '' he said . Diving into general election mode , Obama turned his attacks to McCain , saying it 's `` time to turn the page on the policies of the past . '' `` While John McCain can legitimately tout moments of independence from his party in the past , such independence has not been the hallmark of his presidential campaign , '' he said . `` It 's not change when John McCain decided to stand with George Bush 95 percent of the time , as he did in the Senate last year . '' Earlier Tuesday night , McCain portrayed himself as the candidate of `` right change . '' `` No matter who wins this election , the direction of this country is going to change dramatically . But the choice is between the right change and the wrong change , between going forward and going backward , '' he said in Kenner , Louisiana . CNN 's Candy Crowley , Jim Acosta , Suzanne Malveaux , Paul Steinhauser and Robert Yoon contributed to this report .
CNN : Clinton says she 's not making any promises tonight . NEW : CNN projects Clinton taking South Dakota ; Obama takes Montana . Obama passes delegate threshold . Clinton tells New York lawmakers she will be Obama 's No . 1 .