How is the double taxation on US social security benefits avoided in the case of an US citizen resident in Switzerland?

[Mary67]

Hi, 

The tax treaty between US and Switzerland says practically that the social security benefits (SSB) are taxable in both countries. While for non-US citizens or permanent residents, the treaty provides detailed method for avoiding the double taxation, it is not so clear how it is done in the case of US citizens. 

In the case of Switzerland: is the deduction of 1/3 of the full SSB payment  still applicable? 

In the case of US: does the tax credit include the Swiss tax on SSB?

Thank you.