Australia’s plan to build the submarines with U.S. and British help faces big hurdles. Supporters say they can be overcome. Critics say they may be too much.

Arriving in Europe with an unfinished economic and environmental spending plan, the president will confront new challenges, some self-inflicted, at two major summits.

Jonathan and Diana Toebbe, charged with trying to sell classified nuclear secrets to a foreign power, struggled with finances, family and the state of America.

The British government played an early role in brokering the alliance with the U.S. and Australia to deploy nuclear-powered submarines in the Pacific, officials in London and Washington said.