Huckabee would be dismantled against Obama and Romney would be able to hold his own. Romney has economic credentials Mormonism, Huckabee has Baptism. Keep in mind that the only reason Huckabee was "the last one standing" was because he overstayed his welcome. He had lost long before Romney had. Romney was far ahead of him when he dropped out and would have continued to outperform Huckabee to the end. Huckabee was lucky, not skilled. He relied on his religion to get noticed as the only one still campaigning on social conservatism and skated along directly above the percentage of Baptists in each state. All he has is one strength that happens to give him a nice floor in one chunk of the country. He didn't improve upon that floor at all, proving that he was just the token religious right candidate.
So Huckabee wasn't as much the "last candidate in McCain's way" as he was an annoying chihuahua nipping at his ankles and yipping as he strolled across the finish line.
There is no such thing as "overstaying one's welcome". That is just your way of saying "dropping out later than when I wanted him to".
