a few things about 美国民主选举管理的基本常识

illegal immigrants is more than 未来的票仓 - instead it is quite impactful now.

illegal immigrants are counted in census.  census is the basis to determine number of house representatives and electoral college.  to illustrate with California: total populatoin 39mm, of which about 2.7mm are "undocumented" of some sort.  in 2020, California counted 55 in electoral college.  if exclude the 2.7mm, California would have counted 51 or 52 in electoral college.

most States with higher portion of undocumented are deep blue or blue leaning.  democrats and Biden are not complete fools.  they know well that the flood of illegal immigrants will bring security risk, criminals, and huge burden to tax payers.  but they care more about staying in power.