I am an Italian Visiting Professor entered I USA with a J1 VISA on July 2006. During this time I didn't received any salary fro USA University. I left from USA on October 2006.

I entered again with a new J1 Visa on July 2008. I received regular salary from USA University from this data up to now. On 2007, I claimed for a Tax Treaty to be exempted from Fed and State Taxex. I was exempted from these taxes and also from Medicare tax.

During the first 6 month of 2008 I have been exempted from State and Fed taxes. I paid Medicare.

I ask:
1. when tax expeption period will be end?
2. I should pay medicare during first 6 month of 2008?
3. is tax treaty someway realted to non-resident status?

Thanks

Read about tax treaty with Italy
Your U.S. Tax Return: U.S. Tax Treaties for Professors, Teachers and Researchers

Also go to Form 8843 (at Internal Revenue Service) and read lines 7 and 8. You can get treaty exemption for 2008 only. You have already spent 2006.

You should be exempt from Medicare for 2008 as well.