How could American politicians can get away with such ignorance

I know it's a bit overdue but I was buffled by the report that some nut-case running for president in US has threatened to bomb Macca and Medina if terrorists used nuclear against the US. Well, it's humorous in a way because the senator personifies the perception that Americans are ignorant about the rest of the world. He probably thinks that terrorist with nuclear weapons will freeze, put their hands up in the air and start crying mercy if the Americans threaten to bomb Mecca and Madina.

What I find interesting is how America's top politicians can always get away with such ignorance, he certainly isn't the first. Silvestre Reyes, the democrat's House Intelligence committee chairman thought that Al-Qaeda is Shia and Obama wants to invade Pakistan, one of the largest Muslim countries and a close ally to America.