John McCain's last-man-standing strategy prevailed. Now, onto the general election and the hurdles that come with it.

John McCaim AP PHOTO

"It's an uphill battle. We have a tough fight ahead," the Republican nominee-in-waiting says of his presidential quest — and truer words may never have been spoken.

McCain clinched the nomination March 4, surpassing the requisite 1,191 Republican delegates as voters in Ohio, Vermont, Rhode Island and Texas put him over the threshold. Next up for the party and its new standard-bearer will be convincing a public craving change to keep a Republican in the White House in the midst of a drawn-out Iraq war and a sluggish economy.

That is a daunting task.

But several factors further complicate McCain's run.

Approaching age 72 this year, McCain would be the oldest president ever elected and is certain to face doubts and questions that come with that distinction. His offbeat humor and occasional temper can be grating to even those who know him best. And, his habit of breaking with the Republican Party to work with those across the aisle irks the conservative wing of the party.

Conversely, the Democratic Party is highly energized and will have? either the first female in Hillary Rodham Clinton or the first black in Barack Obama, who is calling for a new direction after eight years of rule by President George W. Bush.

"With that scenario I'd have to withdraw my nomination," McCain joked to media recently on his campaign bus, laughing when one laid out the obstacles facing him and the party. "That scenario's so bleak!"