BYRON YORK: How Jeff Sessions would change the Justice Department.

Trump promised to put an end to cities defying federal immigration law. To do the job, he picked Sessions, who has called sanctuary cities “one of the biggest, most egregious, and most dangerous wrongs now occurring in our immigration system today.”

“Sanctuary cities are together freeing an average of 1,000 criminal aliens a month,” Sessions said in October 2015. “Countless crimes are happening as a result of these never-ending releases: DUIs, assaults, burglaries, drug crimes, gang crimes, and murders.”

Now, some sanctuary cities are gearing up for a fight to protect their ability to defy federal law. Sessions, who as a senator voted for (unsuccessful) measures to crack down on sanctuary cities, last year called on the Obama administration to “immediately take action to withhold significant federal law enforcement funding” for sanctuary cities. It seems likely Sessions would attempt to do that as attorney general, but what other measures he might take are not clear. What is clear, though, is that he would likely exert significant pressure on defiant cities to observe federal law.

There are many other areas that the Justice Department covers — terrorism, civil rights, business and securities fraud, cyber crime, and still more — that will require Sessions’ attention, if he is confirmed. And finally, beyond those, there is the question of what role an attorney general should play in making sure his boss, the president, follows the law like everyone else.

In addition to being busy with all of that, Sessions will likely face significant pushback from his own Department.