David Cameron has won the backing of US President Barack Obama for his stance over Europe.
The President said Mr Cameron was right to see if the relationship can be "fixed" before deciding to quit.
The Prime Minister has faced criticism within his own party for the strategy but after talks at the White House, Obama said membership of the EU was an expression of Britain's global influence.
Cameron has pledged to back a Conservative MP's EU referendum bill, as Cable labelled the move potentially 'damaging' for the country.
114 Conservative backbenchers have voted in favour of a eurosceptic motion to amend the Queen's Speech in defiance of the Prime Minister.
David Cameron has denied he has buckled under pressure from his backbench MPs over the EU debate.