CHEN: It was the the biggest night so far for Barack Obama's political career. In the U.S. city of Denver last night, the Illinois senator formally accepted his party's nomination to run for president this fall. Here's what he had to say. STORY: On the final night of the Democratic National Convention before 75,000 flag waving supporters at Denver's Invesco Field, Barack Obama launched a sharp assault on Republican presidential rival John McCain. [Barack Obama, Democratic Presidential Nominee]: "Senator McCain likes to talk about judgment, but really, what does it say about your judgment when you think George Bush was right more than 90 percent of the time?... I don't know about you, but I'm not ready to take a 10 percent chance on change" Obama -- the first African-American presidential nominee of a major U.S. party -- linked McCain directly to President George Bush --- and said their failed Republican policies were responsible for a faltering economy and a decline in global standing. [Barack Obama, Democratic Presidential Nominee]: "Tonight, I say to the American people, to Democrats and Republicans and Independents across this great land -- enough!... It's time for them to own their failure. It's time for us to change America and that's why I'm running for President of the United States." The Illinois senator made some of the most direct attacks on McCain -- including harsh criticism of McCain's defense of the Iraq war and the pursuit of Osama bin Laden. [Barack Obama, Democratic Presidential Nominee]: "John McCain likes to say that he'll follow bin Laden to the Gates of Hell -- but he won't even go to the cave where he lives." Now that Barack Obama is officially the Democratic presidential nominee, the race for the White House enters a new phase. Democratic leaders are hoping for a big bounce out of their convention and say the party is completely unified-- something it may have to be to beat John McCain in November.