Well, since they historically make up 20%-23% of the electorate, roughly 25-30 million votes, it would eternally kill the Republican party.
America would be perpetually under Democrat rule.
The Founders were big fans of them. See my signature...
KFWA is talking evangelical Christians NOT the traditional/conservative Christians of the Founding Fathers. Evangelical Christianity did not come into play until the very early 1800's.
However, you are right that the Republican Party would go down the tubes if the evangelical Christian left the party as evangelicals make up 50% of the party. Evangelical Christians will never leave the party as they have no where else to go.