What might a by-city Martial Law implementation look like?

Disclaimer: I have no military or law-enforcement experience so I am undoubtedly getting a bunch of things wrong. Read this for ENTERTAINMENT value only.

Just for shits-and-giggles, I want to rough-out a "mission" whereby Orange-Force implements Martial Law on a city with roughly 80k population and a core-area of 20 square-miles. It COULD be Springfield, Ohio but it applies equally to Kalamazoo, Michigan and maybe fifty other cities in the US.

The objective of the imposition of Martial Law is to identify and capture key Purple-Force players for later processing.

Springfield, Ohio

The first objective would be to secure the southern and then the eastern boundary because I-70 is one of the United States MAJOR east-west arteries for over-the-road logistics. Quite by coincidence, the city of Kalamazoo has I-94 along its southern boundary and it is THE major artery between Chicago and Canada. Lots of small-to-medium size cities with large influxes of immigrants are bounded by a major interstate.

Since Springfield is a scant sixty miles from The Ohio State University (and Kalamazoo is home of Western Michigan University) the smart money would run the operation between Christmas-and-New Year, or during Spring Break or two weeks after the University(ies) break for the summer to minimize collateral damages and to reduce the risk of useful idiots reinforcing Team Purple.

After securing the southern flank, the second wave of movement would be to secure the major inbound/outbound roads marked with red score-marks in the image shown above. Simultaneously, "Spotters" would be positioned 30 miles outbound on the interstate to identify inbound busses that might be transporting allies of the Purple-force. Vehicles with radios would tail the busses to ensure they did not exit the limited access roads to avoid road-blocks. Once inside the area where Martial Law has been declared, many of the Constitutional Rights of the riders are diluted and they can be detained.

In weeks before the operation, Artificial Intelligence would be monitoring cellphone vocal traffic and tagging numbers that trafficked in Creole, Spanish, Farsi, Arabic, Mandarin, Cantonese and other languages-of-interest. GPS locations would also be harvested prior to the operation to gain insight into the travel and association patterns of those groups of people. Intelligence would also download the "translation apps" resident on phones.

That information would be harvested ostensibly to "push" text messages to the various groups in their native language but would have obvious tactical advantages to Team Orange.

Food deliveries to retailers inside of the Martial Law zone would be delayed but food would be available at the check-points. The caveat was that the entire household must report to the check-point to ensure the proper amount of food was distributed. 

When residents showed up at the check-points, they would be offered a deal they can't refuse, an all-paid, all-inclusive stay at a resort in sunny Cleveland. There would be sniper over-watch and violent refusals would get a kinetic response. Refugees (why mince words) would be sorted into sheep and goats and dealt with accordingly.

In five days, the population would be reduced by 50%. In ten days the population would be reduced by 90%.

Then the door-to-door sweeps start. If done at New Year or Spring Break, IR will identify inhabited houses and Purple-force movement. If the op is run during the summer, seismic sensors must be "sprinkled" and drone coverage must be continuous.

Take-aways:

Never consent to becoming a refugee.

Beat the rush, panic early and ALWAYS have multiple options of places to land. Even better, have a change of clothes and a few other necessities stashed there.

It is always good to have a friend or family member who works in the mail-room of the local LEO office. Since mail-rooms are extinct, the closest relative is knowing somebody in IT.

There will be a pulse or a tempo to operations. No sane general would attack Russia in December. Likewise, there are "good" and "poor" times to run Martial Law ops in the US.