Philippine President Rodrigo Duterte said he may step down as early as next year once a new constitution, which will pave the way for a federal shift in government, is in place.Duterte, in a televised speech late Friday, rejected suggestions that a recently concluded review of the nation’s charter is meant to prolong his stay beyond his six-year term, which ends in 2022.“I suggest and I would like Congress to approve it – make my term co-terminus with the beginning” of a new constitution, Dut