Match each term with the phrase that best defines it. sectionalism
the idea that states should hold the most
political power
to invalidate something or make it null and
void
popular sovereignty
states' rights
the idea that people should be able to vote
on important issues
nullify
concern for one's region over concern for
the entire nation

sectionalism  - concern for one's region over concern for  the entire nation

popular sovereignty  - the idea that people should be able to vote  on important issues

nullify  - to invalidate something or make it null and void

states' rights  - the idea that states should hold the most  political power

Explanation:

Sectionalism can be seen the most when we have certain quarrels between certain regions.

The best example of popular sovereignty was when the new states were choosing whether to enter in the Union as a free state or with allowance of slavery.

In general when we are nullifying something, we are actually making it without value.

States' rights is the doctrine according to which government should have the supreme authority.

i think it was   tsar alexander ii