Use the Individual Taxpayer Identification Number program for Non Residents a base for immigration reform.

Since 1997, the IRS authorized by the US congress, started to collect income taxes on non resident aliens, depending on their immigration status but to meet taxation laws on income.
Using this tax program for immigration reform is plausible for many people to pay income taxes despite their immigration status.
Immigrants or non residents without status who have paid income taxes would be eligible, as they have paid their fair share. The Tax ID number is not a Social Security number and does not entitle those who have a TIN to social security benefits.
Any immigration reform should start with those who pay taxes. People who pay income taxes should be considered for immigration reform first.