Did you know that this is actually the 18th time the fedgov has "shut down" since 1976?
These included 1 shutdown for 10 days under Ford; 5 shutdowns in 18 months, for a total of 57 days under Carter (with dem controlled house and senate no less); 8 shutdowns for a total of 14 days under the 8 years of Reagan (none longer than 3 days); 1 for 3 days under Bush; and 2 for 26 days under Clinton.
Mostly these things happen because of the Antideficiency act, which, if an executive branch administrator has been found in violation, can cause them to lose their jobs, and possibly face civil and criminal penalties:
My favorite shutdown?
4 of the 5 Carter shutdowns were because of debate between northern and southern Democrats about whether medicare could fund abortions only in the case of danger to the life of the mother; or whether there should be an exception for rape and incest. The rape and incest northern Democrats eventually won.
Note... there was no "Republican obstructionism" involved... it was southern Democrats vs. northern Democrats on this one...