Sure can. Isn't even particularly difficult.
Only a majority vote in the legislature of the state affected and in Congress is required, making it a whole lot easier to get through than an amendment,
US Constitution, Article 4, Section 3: New States may be admitted by the Congress into this Union; but no new States shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress.
Proposals have been made to split most states at one time or another.
http://en.wikipedia.org/wiki/List_of_U.S._state_partition_proposals
Texas has the right to split into up to 5 states as part of the agreement that brought it into the Union, if Congress agrees. This would give TX 10 senators.
Come to think of it, this could be used to give one side a permanent majority in the Senate.
Conservatives have a healthy majority in both Houses of Congress.
They pick out the 20 most conservative states and break each up into three new states. The relevant legislatures and Congress approve the transaction.
We now have 110 states and a permanent 2/3 majority in the Senate.
President doesn’t even get a chance for a veto.
WOW! The Constitution becomes mow awesome the more you find out about it. Maybe the real HOPE lies there.
I’m not sure you can form a state from within a state. If you look at Article 4, Section 3 where it states “but no new States shall be formed or erected within the Jurisdiction of any other State”. That phrase is bordered by semicolons, meaning it’s a separate thought from the one listed behind it where it says “nor any State be formed by the Junction of two or more States, or parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress”. That means, to me, that the part where the states Legislatures (notate plural) and Congress are mentioned is only if the “new state” is created out of parts of more than one state.
Just my opinion but those semicolons are there for a reason.