They just go together.
First, John McCain's statement that this nation was founded upon Christian values and therefore he would prefer a president with a "solid grounding in my faith" to a Muslim.
The statement is stupid because it is ignorant: there is no such thing as Christian values without reference to Judaism. Indeed, it is when Christians lose sight of the history of their religion and its foundation in Judaism, that Christians lose touch with morality (Inquisition, Crusades) because they deny their own precedents and forget that their own Gospels show that but for a Jew, there is no Christianity.
The statement is also ridiculous. Other than the personal religious test McCain imposes upon presidential candidates, the notion that Muslim or Hindu or Jewish values are at odds with American values and principles is rubbish. Millions of people of those religions live and prosper in America as integral parts of this society. Indeed, America's assimilation rate for Muslims is one of the primary reasons that insane jihadi nutters have so little success turning local mosques into an American equivalent of the Finsbury Park Mosque in London. Those 9-11 hijackers were not born and raised in America, yet so many European terror cell members are Muslims born and bred in their respective countries (Germany, France, UK).
Second, the criticism of Rush Limbaugh by Senate Democrats. The statement Limbaugh allegedly made was calling anti-war troops "phony soldiers." The statement he actually made was to call Jesse MacBeth, a soldier who lied about his status, awards and training, and popped off in antiwar comments to the media, a "phony soldier" because he washed out of boot camp and never went to Iraq and saw the horrors he claimed to have witnessed. The Democrats are being completely disgusting about the whole affair, but that's because the story is too good to pass up, regardless of the facts.