In a lot of areas, I agree with you that Obama has done a good job. Especially when you take into consideration the amount of blind objection he's dealt with in the last 8 years by Republicans. To the best of my knowledge he has done his best not to blame Bush for most of the mess he walked in to.
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I think his foreign policy, especially with stubborn leaders is weak though. From my perspective, this tends to be the case with Democratic Presidents. I believe this comes from their desire to resolve issues in a civil manner and preference not to escalate to potential war. Our opponents know this.
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From a diplomatic perspective, I believe that there is only one way to deal with stubborn leaders. The use of ultimatums. They are only effective if you carry out the consequences as quickly as you issue the threat. It sucks when we have to do it but demonstrating the willingness to see things through can be a powerful motivator to keep our future opponents at the table for civil discussion.