The answer to all of these questions was answered by Bodhi above - if it's not a constitutional power and it's needed (meaning, we the people want it), you amend the constitution. It was literally written so it can be altered as needed over time.I don’t disagree that the federal government is bloated and spends irresponsibly. But if libertarianism is the answer, I’m genuinely curious about how it handles some real-world complications.
If we limit federal power strictly to what’s enumerated in 1787, what’s the plan for everything the framers couldn’t have imagined  things like air travel, cybersecurity, nuclear energy, or pandemics? Would we let fifty different state systems handle those separately? Wouldn’t that invite chaos every time problems cross state lines, which most modern ones do?
Libertarians emphasize personal responsibility, which I respect. But how does libertarianism address outcomes that have little to do with personal choice  like being born poor, disabled, or in an area with unsafe water or failing schools? If the answer is “private charity,†what evidence suggests that private giving can scale to replace public safety nets in a country of 330 million?
You mention cutting departments like Education and Agriculture. If those vanish, who coordinates student loans, school standards, food safety, and agricultural disease control between states? Markets? State compacts? Without a coordinating framework, how would we keep economically weaker states from being left behind  with lower standards, unsafe products, and underfunded schools?
And when it's said that “the government shouldn’t tell people what to do,†does that include pollution rules, building safety codes, or vaccination requirements? At what point does one person’s “freedom†from regulation become another person’s loss of clean air, health, or safety?
I’m not asking these questions to score points  I’m genuinely wondering how libertarian principles scale in a complex, interdependent nation. Because in theory, “leave everyone alone†sounds elegant; in practice, it risks leaving a lot of people unprotected, unheard, and left to fend for themselves in a system that quietly rewards the powerful.
Libertarians have no problem with the government performing within its enumerated powers.
 
	 
	 
 
		

 
 
		
 
 
		

 
 
		 
 
		

 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		