It is already tax season here in the US and as a matter of fulfilling our civic duty, we are all expected to file income tax returns and pay taxes whenever required to do so. All - which means US citizens, greencard holders, and even undocumented immigrants, are required to file Form 1040 to the Internal Revenue Service.
You may be surprised but a large number of undocumented immigrants pay taxes as well. Usually, one must have a Social Security Number to file a return, but the IRS allows those who do not have one to use ITIN or Individual Tax ID Number. These immigrants hope that paying taxes could someday afford them an opportunity to help in legalizing their status notwithstanding their violation of immigration laws. Though being undocumented disqualifies them from claiming certain tax credits, or getting social security payments or Medicare benefits, they still feel that it is a small price to pay when compared to not having filed taxes at all.
Also, bear in mind that the undocumented also pay taxes in other forms either by way of a payroll tax, sales tax, or property taxes. So even by not having to file their taxes, the undocumented, just like the rest of us also has to share in the collective burden of funding critical programs and projects such as our public schools and local health services.
Most immigration reform proposals offered by various proponents in the government include the requirement that before an undocumented becomes legalized, he must show that he has been paying taxes regularly. The undocumented hopes that this can be the case so that when it is time for them to file for a greencard, they can provide proof of a paper trail detailing that they have been dutifully paying their taxes. This signifies their willingness to adhere to the laws of the United States, most especially its tax laws.
And the undocumented need not fear. The IRS does not share their ITIN or their immigration status with the USCIS. Between filing taxes then paying for it when it is due or not having filed at all, I believe the former may give the undocumented at least the glimmer of hope that USCIS looks at their situation in a more humane and compassionate consideration.