BOSTON (AP) — After nearly six years trying to become president, Mitt Romney conceded he had lost to President Barack Obama early Wednesday morning, declaring that “this election is over, but our principles endure.” “I believe in America,” Romney said one final time, repeating his campaign’s slogan, decided long ago. “I so wish that I had been able to fulfill your hopes to lead the country in a different direction. But the nation chose another leader.” The former Massachusetts governor lost the race after nearly 17 months of fighting, gritting through a prolonged primary and enduring a summer of Democratic …