What makes x,y,z the domain of the federal government and what makes other things the state's/province's?

The law. The constitution.

Thank the founders of the country,

Somethings are off loaded to states and provinces,others they want control of.

@elbanditoroso and @SQUEEKY2
But what criterea are used? What doesn’t affect the whole country?

In the US Constitution it says all matters not assigned to the Federal government are reserved to the states. I don’t know about Canada.

This is actually a good question. The Constitution isn’t a great answer. The constitution makes no mention of weed and there is a debate if it should be a Federal or State thing.

If the Federal government wanted (and Sessions does) they would repeal the laws legalizing marijuana in multiple states and make it a Federal mandate.

It is a evolving beast and there is no list of what belongs to each.

Immanent domain.

The Federal Government is the big boss. What they dictate is the final word.
What the Feds don’t legislate, the States may address.
What the Feds or the State don’t address, the local counties may control.
Hence, alcohol is legal with the Fed, and the State, but illegal to sell in some counties.

The Federal Government, under Article 1, Section 8, Clause 3 of the U.S. Constitution (the Interstate Commerce clause), gives Congress the power “to regulate commerce with foreign nations, and among the several states, and with the Indian tribes.”

This has been used to give the Federal Government jurisdiction over a lot of things.

Another way is the power of the purse. A state will not get Federal Highway money unless it agrees to certain laws. That is how Nixon got the national speed limit set at 55, and how the lobbying by M.A.D.D. got the national drinking age raised to 21.

It’s a good question for more reasons than you might think. Chief among them is the fact that increasingly it is the Federal government taking up the slack from fund starved states in maintaining our equilibrium.

There’s no set criteria for this as to what should belong to Feds and what to States apart from things like National security / external affairs etc. It all boils down to who wants to control what.

No it’s deeper than that. The Feds are responsible for the national defense as well as policing criminals whose endeavors cross state lines, which is why you wind up in a Federal prison when you send that joint to your cousin through the mail.

In principle some things are left to the states instead of being enacted at the federal level because of cultural differences across various parts of the US. A law that is appropriate for the urban areas that make up most of Massachusetts might not be useful or reasonable in the plains of Wyoming.

In reality, things often end up getting punted to the states because it’s easier to pass legislation through the federal Senate if Senators can be assured that their state doesn’t have to enact certain more controversial portions of the bill if they don’t want to.

In other cases, law diverges from state to state because of enforcement practices. The Supreme Court has maintained that the federal government cannot prosecute state governments for refusing to enforce federal law. This is how we get things like state-level marijuana legalization. It is still illegal at the federal level, but an Obama-era memo indicates that the feds won’t go after people for breaking marijuana law, and certain states have decided that state-level law enforcement also won’t go after people. That’s also how you get things like sanctuary cities, etc.

Another example of this is when the Affordable Care Act was being debated in 2009, originally it was going to include its expansion of Medicaid at the federal level. But the way they were going to make states comply was to threaten them with the removal of all Medicaid funding if they didn’t, and the Supreme Court ruled that this punishment was so severe that it was akin to prosecuting a state for not upholding federal law, which is, again, unconstitutional. And that’s how we ended up with Medicaid expansion as an opt-in program, which I personally think kind of sucks, because there’s no reason why a poor person in Wyoming doesn’t deserve access to healthcare as much as a poor person in Massachusetts.

This whole principle of not being able to punish states for breaking federal law had led to all sorts of fuckery in recent months. A little while ago, Idaho decided to just blatantly ignore the Affordable Care Act and start telling insurers they could resume discriminating against people with pre-existing conditions again. Luckily CMS decided to bring down the hammer. I didn’t think they would; I was sweating about it for awhile.

Thanks for the answers and thanks @stanleybmanly for appreciating the OP.
Now I’m going digest the answers.

By the way there were no GAs (given?) starting from @janbb‘s post.
@kritiper ? I actually looked up the word instead of assuming it’s a spelling error.

@flo That’s what they call it here when the person who owns the land doesn’t want to sell it. The state, county or government holds ultimate claim.