Mr Obstfeld's stance on Greece suggests a view that debt gets dangerous when it climbs above a certain level. When asked in April 2013 if countries "risk losing control of their own fiscal sustainability" if they let their debt loads get high because of "an adverse feedback loop in which doubts by lenders lead to higher government bond rates, which in turn make debt problems more severe", he replied "strongly agree", with a confidence rating of 10. He added: