Local law enforcement doesn't have the authority to detain them for being here illegally, nor do they have the authority to deport them. That's why I'm recommending this as a viable solution rather than complaining because laws aren't being enforced.
If you like my idea, call your Congresscriminal and lobby to get local law enforcement the authority to deal with criminals.
"Okay... so ... why arent they in Mexico after conviction/arrest? ... We need local law enforcement to help."
"Local law enforcement doesn't have the authority to detain them for being here illegally, nor do they have the authority to deport them. That's why I'm recommending this as a viable solution rather than complaining because laws aren't being enforced."
Those are exactly some of the problems that HR 4437 is fixing.
Even under current law, it is legal for a local police to check immigration status and give INS a call, and hold until they are under Federal detainment. Sometimes this is done. But there are issues of funding and law enforcement policies, etc. that get involved in the local enforcement 'doing the job of the INS'. The CLEAR Act addresses this problem.
The 'detain' part can be resolved by making illegal presense a criminal offense (felony not needed), and deportation can be addressed by getting enough beds to end the 'catch-and-release' flaws in the system.