It'd be hard to argue otherwise. I mean, just think about it. Who was the first president to die in office? William Harrison, a Whig. Who was the second? Zachary Taylor, a Whig. The Mexican-American War couldn't kill him, but joining the Whig Party? That was a step too far. Of the four Whig presidents, none of them served a full four year term. Even John Tyler, who basically served for four years, got kicked out of the Whig Party early into his presidency.
Can it really be a coincidence that the first two presidents to die in office were Whigs? And who was the third president to die in office? Who was the first president to be assassinated? Abraham Lincoln, a former Whig. Even escaping to the Republicans couldn't save him in the long run.
How could the Whigs fall apart after only twenty years? Other major parties have survived far worse calamities than the Whigs. The Democrats got blamed for the Civil War, but they rebounded. The Republicans got blamed for the Great Depression, but they rebounded. Yet the Whigs couldn't... How odd.
Even John F. Kennedy, a Democrat who got assassinated, definitely has the aura of a Whig. Not only are you not allowed to be a Whig. You aren't even allowed to be similar to one.