i will use the USA as an example. there are just too many people in the US to deport. what needs to happen is an over haul of social programs, citizenship and some privacy rights. it would be like this.
Step1: stop all social programs in place that help illegal immigrants(it will help give them incentive to follow through with step 2 so they can receive some help as a citizen while paying income taxes so that way they pay some kind of money back into the system). also stop anything in favor of illegal immigrant, make it unfavorable to be an illegal immigrant in the US so they want to receive citizenship.
Step 2: make a law that can give existing undocumented immigrants immediate citizenship by going to a government run establishment and applying( it will be a one time thing that takes all day or so, they fill out papers, get a social, etc. then go on their way as a us citizen). at first while this process is happening, an appropriate time window will be given for the estimated number of illegals in the country to do the quick program so everyone gets a fair chance to receive citizenship.
step3: make a law saying that if a cop pulls you over and thinks your not a citizen, they can ask you for proof of citizenship. if there is no proof they will arrest you and take you to the station and the police will look from there. if there is still no proof, the presumed illegal will be immediately deported. there will be no hearing weeks later that the illegal will never show up to. they are handed over immediately to border patrol and immigration. These people in this situation had a chance to apply to the easy program explained above and didn't, meaning they don't want to be a citizen and have alterior motives for being in the US. If they don't want to be a citizen, they don't deserve to be here.
Step 4: make this the new process for all immigrants coming into the country. At the border, patrol would take finger prints of non citizens entering the country and give them 6 months to go and get citizenship. This finger printing would help show that these immigrants are still in the "transition" period. If they were pulled over and an officer suspected they weren't a citizen they could have proof of a "transitional immigration that will soon attain citizenship. This also again helps show if the immigrant did not transition within the allotted time line and show they have no intention of becoming a citizen, giving a right to be deported. To help keep this system fool proof, an immigrant is allowed 3 transitional periods that are a year apart starting from the date they were deported. after the third time if they still haven't applied to the super easy system to become a citizen, they will be deported forever. These particular individuals would have their names, finger prints, and physical descriptions input into the system forever so if they ever tried to reenter the US, they would come up on the "forbidden" list and not be allowed to enter. If for some reason they were to enter without getting caught, this would again provide officers with reasonable suspicion, that this person is to be deported immediately. Deportation would also be allowed for those in the transitional stage if they are suspected terrorists, drug traffickers, a criminal in their home country, etc. anything that puts citizens at risk.
This is what i would do for our broken immigration system. More citizens in the US who can be taxed is a positive thing. It would help build our economy and build the labor force we need.
VOTE FOR ME IN A FEW DECADES: PAIGE BALLARD