Yes, Donald Trump could absolutely be the Republican nominee in 2016
This he backs up with numbers, and a telling photo of a 'yuuge' Trump crowd in blue Massachusetts. I'd go one step farther and say Trump "could absolutely be" the next president.
These are tough times in which President Obama, to whom Clinton is tightly tied, is utterly wimping out. Such times do not reward Obama's vaguely obscene and definitely metrosexual "leadership from behind."
Trump's tough talk could resonate with the electorate as did Teddy Roosevelt's. After a prolonged drought, voters may well crave a leadership testosterone fix, which Trump is best able to provide.