Mayor Bloomberg waded into the national debate on immigration reform yesterday.

“[This] is neither a Republican issue nor a Democratic issue; it’s an economic issue,” he said at the New York Stock Exchange, where he joined News Corp. Chairman Rupert Murdoch and other business leaders in backing a proposal to make it easier for US firms to hire talented foreign workers. (News Corp. owns The Post.)

“If we keep the best and the brightest out of this country, all the next big things will happen outside the country,” said Bloomberg, who on Wednesday blasted Congress for making “a mess of our country.”