Most policy change isn't done by new law
One thing that trips a lot of people up about our democracy is the concept of executive governance. Everyone sort of has the civics-class model in their head of "the legislature makes the law, the executive enforces the law, and the judiciary interprets the law," but that really undersells what goes in the the executive branch.
And so I think a lot of people think policy development is mainly a legislative function when it's really an executive function.
What the legislature does do is layout broad dictates of policy goals, and then provide the executive with the authorities, resources, and boundaries of how to get the job done.
But when Congress wants CAFE standards in cars they don't tell the executive branch how they are going to actually test the cars or how often or at what point in the supply chain, and when Congress wants a COVID vaccine made and distributed they don't need to decide whether the distribution system is going to rely on state health departments or private sector pharmacies or UPS home-deliveries.
Those are problems for an executive to solve. And they are tough problems! And that's why Hamilton wanted "energy" in the executive. It's all well and good for Congress to want to reduce illegal immigration. But actually doing it is tricky, and there are lots of different ways to go about it, and smart executive policymakming will do better than poor policymaking. But a huge proportion of policy success and failure rests on the executive; no amount of good lawmaking can overcome poor executive policy implementation.
When I teach this in class, I always talk to undergrads about planning a Friday night house party. You sit around on Tuesday with your friends and set the general terms of the party: who to invite, what the theme will be, how much food and beer to buy, and how much money you are willing to collectively spend on the party. That's the legislating.
But then you hand it off to executive decision-making. Someone or some group of people need to actually make the invitations, and buy the food/beer, and figure out the music, and put up the decorations at the house. And they are going to have a lot of discretion! Maybe they go for Utica Club and Buffalo wings to save money, and grab a campus band to perform live. Maybe they get the thing catered by Chick-fil-A and resort to just using Spotify for the music. Maybe they are really into decorating and you get a completely transformed house. Maybe they are lazy and you get nothing for decorations. And you never discussed when the party was going to start and end, so they came up with 9pm-2pm.
And ultimately, the quality of the party falls on them. This will be a familiar dynamic to anyone who has every participated in a PTA. A lot of people help make the legislative decisions, but it's the 2 or 3 moms who spend seemingly all their free time working on stuff that actually make field day and the run-a-thon and the food drive happen. And when their kids age-out of the school, people panic. Someone needs to step up and be the executive! And when the quality of the leadership goes down, it's obvious.
Circling back to the federal government, it's also important to remember that most policy change doesn't happen via lawmaking. If something is going wrong in the executive branch with policy, it is of course totally reasonable and normal for Congress to provide more/less money or alter/restrict the authorities the executive branch has. This is banal and routine.
But most of the time, policy change---even policy change initiated by Congress---occurs simply by the executive branch changing the policy. You don't need new laws to improve the availability of COVID tests, and you don't need new laws to change CBP/ICE tactics in Minnesota. You just need decision-makers to decide that current policy isn't working and new solutions are necessary. Most congressional oversight hearings don't result in new legislation; but many of them do bring about policy changes, simply because Congress tells the agency folks, dude, try a different approach here.
And I think this is something people get wrong about Congress. They look at a problem in the executive branch and see Congress didn't do anything about it in terms of legislative output, and they decide Congress is asleep at the wheel, or "not doing their job." Sometimes this is true! But just as often, Congress is brining about change in executive branch policy via the informal mechanism of representative democracy: highlighting problems, yelling at executive branch officials, or---more often than you think---just politely asking them to try a different approach.
This happens all the the time when you have a committee and an agency with a good working relationship---phone calls go back and forth, and the agency and committee work out a resolution that adjust some policy. But it even happens in more adversarial situations. The president's recent 180 on Greenland is great example of informal congressional pressure; in fact, war powers is place where Congress routinely boxes in presidents without actually doing anything legislatively. Statements from members, symbolic votes on the floor, and private phone calls are often enough.
I don't expect CBP/ICE policy to differ here. Congress may put in some actual new restrictions in law on both agencies, but more likely what we are going to see is a bit of a shakeup of policy approach by the executive branch. The current street-sweep focus approach in Minnesota has always been a distinct policy choice favored by some elements in the administration, particularly those who like the confrontations and spectacle of it.
But it's far from the only way to go about deportations, and alternative policy choices---be it a renewed effort at pursuing criminals or new effort at focusing on businesses---are available and favored by other factions in the administrations. I suspect those factions are going to have their day shortly, and not because Congress has demanded it in law, but because enough Members have made clear that the current policies are not working.
It can be hard to untangle this from public opinion, which also has an independent effect on executive branch policy. And in some sense, it's all the same thing---it is called the House of Representatives, after all. But in another sense it doesn't really matter, because public opinion and Congress, regardless of the direction of causality, tend to work in tandem on such issues, and both have their impact without formal changes to law.