Early efforts were thwarted by serious cultural, religious and psychological barriers.

Immediately after the war there were several serious barriers for foreign businesses to set up operations in Cuba.

This indicates serious institutional barriers to success within those institutions.

Certainly, the two sides lack coordination and cooperation, which alone is a serious barrier to reconstruction.

Thus there was a serious barrier to becoming a Republican.

No matter how qualified she might be, she'd have to overcome some serious barriers just to get a chance to prove herself.

The second thing is that there are serious barriers to providing blast mitigation.

In practice, this translates into a serious barrier to democracy.

In the energy sector, you are right to be concerned that the facts show serious barriers to competition.

We need nuclear energy and it would act as a serious barrier to other crises that may arise.