Bring back the death penalty
I agree this option is needed in order to negotiate and compel people to cooperate with authorities. However, logistically it is too expensive and drawn out to impose in practice. A better alternative may be to revoke citizenship for people; build a joint prison program with Mexico to handle illegal immigrants who commit violent offenses on either side of the border, and enforce that with military bases for training that double as border security, and also deport citizens there for life as an alternative to the death penalty.
I think people would be more afraid to lose their citizenship if they fail to comply with laws and with the justice process. Any obstruction of justice could void someone's right to paid defense through the state, that I would recommend require full and complete compliance and cooperation. I would have citizens sign agreements in advance to either pay the costs of any premeditated crimes committed abusing weapons or violence, or agree to work off these debts in a prison exchange program, where immigrants can qualify to take the place of citizens for the length of the sentence. The money/labor owed would be proportional to the severity or duration of the crimes or violations, including labor or immigration laws.
And people guilty of drug/human trafficking that led to capital crimes could work in prisons for life, taking the place of women/children currently enslaved in sweatshops so they can go to school instead. In short, there would be equal consequences for either using freedom in this country to lead a productive life, go to school and/or work as law-abiding citizens, or for abusing freedom to violate the rights of others and trade places with an applicant on the waiting list who would welcome the chance to work an honest living!
That is a more effective way to enforce laws, rather than the death penalty. If you read through news articles on any given day, there are more murders by people trying to escape prosecution to begin with, than there are cases of people sparing their victims trying to avoid the death penalty. That is not what they are thinking about when they are set on killing someone. At that point, the ones really focused on committing crimes without regard for others are even willing to DIE to defy the process of justice at the hands of authority. So the death penalty does not deter these people; what deters people is CONSISTENT consequences that aren't worth the trouble, and the death penalty is not guaranteed. It mainly affects people after they committed a capital crime, and are facing a plea bargain to lessen the punishment if they cooperate, so I agree it does serve this purpose.
The short period of drop in crime after an execution is only temporary; where the real factor is "consistent enforcement" that deters crime. The death penalty is NOT consistently enforceable. That is where I believe revoking or granting citizenship based on whether one agrees to follow laws, would be regularly enforced and send a strong consistent message on an ongoing basis. There must be consistent CONSEQUENCES for law enforcement to be taken seriously.