Background
I was on F1 for whole of 2008. Did not pay any FICA taxes
My wife was on H1B for whole of 2008.

Last year, we did married filing separately as F1 students generally file 1040NR and H1B files as residents 1040.

Questions
We want to file jointly this year 2008 to save taxes as I had too less a pay and my wife will owe taxes if she file separately. If we file jointly I'll be considered as a resident. Since I did not pay any FICA taxes in 2008, is it possible for us to do married filing joint.

Can IRS come back and ask me about FICA taxes? Can I prove to them that since I as a F1 I don't need to pay FICA under the india treaty exemption? If yes, how? Is there a way out ?

To be more specific - If I elect to be a resident for 2008 purposes (as my spouse is a resident), can I suspend the election for 2009 (as I would not want to pay FICA taxes and also file jointly in 2009)

You can file joint return as residents. In that case, you must start paying FICA taxes from 2009.

Actually, you are STILL exempt from FICA taxes as a student. See link below.

Nonresident Spouse Treated as a Resident

I filed married filing jointly for 2008.

For 2009 I am still confused if I should ask my employer to deduct FICA. The link that you posted does say that I need not pay FICA as I will still be a student (F1-OPT) till Oct.

But how do I prove my student status? I cannot file form 8843 (the 8843 treaty exemption asks for other details to prove that I am a student) as that form can be filed only with 1040NR

If you filed joint return as residents for 2008, you chose to be treated as resident. So you must pay FICA taxes in 2009. You can not claim treaty deduction.

You can write to IRS that you do not want to be treated as resident for 2009. Then you will not pay FICA taxes and must file nonresident tax return. In future you can not make election to be treated as resident unless you yourself meet SPT.

MukatA:

Read the link I provided. It specifically states:

If, at the end of your tax year, you are married and one spouse is a U.S. citizen or a resident alien and the other spouse is a nonresident alien, you can choose to treat the nonresident spouse as a U.S. resident. This includes situations in which one spouse is a nonresident alien at the beginning of the tax year, but a resident alien at the end of the year, and the other spouse is a nonresident alien at the end of the year.

If you make this choice, you and your spouse are treated as residents for your entire tax year for the purpose of your federal individual income tax return, and for the purpose of withholding U.S. federal income tax from your wages.

However, for the purpose of Chapter 3 withholding you may still be treated as a nonresident alien. Refer to Withholding of Tax on Nonresident Aliens and Foreign Corporations (Chapter 3 of the IRC) in Tax Withholding Types. In addition, you may still be treated as a nonresident alien for the purpose of withholding Social Security and Medicare tax. Refer to Aliens Employed in the U.S. – Social Security Taxes

A4Ashu:

All you need to show is your current F-1 visa to proof your exempt status.

a4ashu:
Yes, AtlantaTaxExpert is right about FICA taxes.

Great! Thanks for confirming.
And thank you so so much for taking time out to answer my questions.