There's always going to be some amount of increased government spending when reform of any type is attempted. That's just always the case when you have to teach people -- especially when they're bureaucrats -- new ways of doing things. But enfranchising all those people and making them legal taxpayers should be well worth the cost.
I believe there are scenarios with immigration reform that will increase government spending. This will very much depend on what is done with immigration reform because there are a lot of different options, all of which, make a difference as far as spending. If we decide to deport them, the cost will astronomically high. If we keep them here, there will be more administration cost, however, they'll be paying taxes in, in the future. So the cost for that option is far lower.
With the coming immigration reform, more Mexicans will be allowed to become naturalized US citizens, which will lead to the government having more people that they are responsible for. This will, inevitably, lead to tax increases. It is a vicious cycle. More immigrants will take away from the decreasing job supply we now have, as they will take a large part of those. And most will not have jobs or any legal source of income, so they will be dependent on the welfare system...
Immigration reform will not increase government spending. This is because of the fact that government spending will go down for things like welfare if less people are taking jobs that people would otherwise have if there weren't immigrants to take them for a lower pay. This is why immigrint reform will not increase government spending.
Immigration reform could do a lot more for people by helping people become legitimate citizens. This would mean that people would be able to participate legally in our economy and could bring a lot of wealth to the country. There would be some spending in terms of possible tax payouts, but not too much.
Once the details of immigration reform are hammered out and put into practice the government will save money not having to pay a bunch of white politicians to argue about the fates of a bunch of minorities they don't care about. They will then allocate less money to the border patrol programs to detain these people and use this "new" money to fund frivolous stupidity they've decided their constituents need when most of the working class people need fewer politicians and more jobs and government programs to bring the work back to the US.
Then the congressmen will find other ways to waste money and we'll be no better off then before.
Immigration reform will decrease spending by streamlining the process to legal naturalization. With less focus on deporting individuals who are already here, while also making it more difficult for illegals to work, we will give immigrants the opportunity to lead honest lives and strive towards realizing the American dream. If the need to come to the US illegally diminishes, the high budgets for ineffective border protection can be slashed.
It's been estimated that the total cost of deporting all undocumented immigrants in the U.S. might be between $250 billion and $280 billion. There's a better, more cost-efficient way to solve this problem. Also take into consideration that many of these immigrants work in the agricultural industry -- basically, they are feeding the rest of the U.S. If we forcibly removed all immigrants from our country, we would face a huge shortage in farm workers.