Being loved and feared is better, and possible.
Extremists don't fear the United States. They are prepared to die while attacking it.
There is not much that any president can do about that. You can try to stop attacks, and most times, the US succeeds in doing that, but stopping all of them? That is just not possible.Earthling's right, J.J., you can't make them 'fear' the US, in any sense which would dissuade them. Embassies have to be defended by having first (and most importantly) a high level of influence over or ability to rely upon the host country State and security forces, and secondly very effective embassy security.
Personally I think it would be a very good idea - perhaps it would eventually be a necessity - to relocate embassies in Muslim countries to isolated areas well outside the city, where approach by anyone could be better monitored, with checkpoints, large US-controlled 'grounds', kill-zones, etc. Think of something like a cross between the current embassy in Baghdad and the Green Zone.