Where Are The "Birthers"?

"Birthers" questioned Obama's right to be President because they said he wasn't born in the U.S.  This in spite of the fact that his mother was a U.S. citizen. Their argument was that being born in a foreign country, he wasn't a "natural born citizen". Now Ted Cruz is showing signs of running for President and he admits not being born in the U.S. so his country of birth is indisputably Canada. My question is, where are the birthers? Why are they not rising up in opposition to Ted's candidacy?