Defense Secretary Ash Carter heads to Brussels this week to try to persuade partners in the 66-nation coalition against the Islamic State group to take on a bigger share of the load.

Some key takeaways about that effort:

— The U.S. believes many members of the coalition aren't doing their share to defeat IS, particularly European nations and Gulf states. "There are a lot that need to make more contributions," Carter said.

— Carter wants other nations to listen to the U.S. strategy for recapturing IS strongholds in Syria and Iraq and then "make an assignment for themselves."

— The Netherlands and Saudi Arabia have promised increased support in recent days. Canada plans to quit airstrikes in Syria and Iraq but expand training of local forces and provide more humanitarian and developmental aid.

— Over the past 15 years, the U.S. has frequently had to plead with and cajole the Europeans to make bigger contributions to the war effort in Afghanistan and Iraq.

— The air campaign in Syria and Iraq is advertised as a 13-nation undertaking. But of the 10,060 strikes conducted over the past year and a half, U.S. warplanes conducted all but 2,332.

— The U.S. also wants Europeans to do more to help empower local armies in Iraq and Syria by partnering with them for training, equipping and advising — without doing the fighting for them.