The US Senate has rejected a Republican plan to replace President Barack Obama's signature healthcare policy. The 57-43 vote defeat marks the start of a days-long debate that critics fear could deny healthcare to millions of Americans. The Better Care Reconciliation Act (BRCA) was crafted over two months but attention now turns to other options. President Donald Trump has urged senators to pass a bill, without indicating which one he supports. Other attempts to replace Obamacare have collapsed in recent weeks due to divisions in the party.