Guys - international politics are not the result of people who are "weak" or "strong". The people involved with international politics are far too pragmatic for that kind of emotion-based reasoning.
The Ukraine/Crimea situation will play out from the results of cold, hard calculus: Russia knows the West can at most use sanctions to dissuade them. They are in the driver's seat, and will simply decide whether sanctions are worth what they get for annexing Ukraine.
The Middle East situation will play out from the results of cold, hard calculus: Israel and even the Palestinians arguably have more to gain with the status quo than "peace". The West cannot force them to decide otherwise. So nothing changes.
The Iranian situation will play out from the results of cold, hard calculus: Iran knows the West will not invade, so they will simply decide if guaranteeing their borders to be inviolable (which is what possessing nukes would mean) is worth the short-term pain and possible unrest due to sanctions.
Nowhere does "oh that Kerry is a pushover" factor in. This isn't a television soap opera.