An individual can exclude (form 8843) the number of days they were in the US as an exempt individual (F1 visa, 5yr limitation) for the purposes of substantial presence test and file taxes as a non-resident. It seems like this is at the option of the individual. They also have an exemption from paying FICA taxes.
If they decide to not take this exemption and file taxes as a resident instead (to take benefit of MFJ status & some credits), would they now be liable for FICA taxes? The employer did not report any "Social security wages" on W2.
