Three reasons mainly. 1) Republicans lost in 2012 and are sore losers. 2) Some radical republicans are using a government shutdown as a photo op to help in their reelection bids come next Nov. 3) Republicans are fearful of the ACA being a success and embraced by average Americans and are willing to do whatever it takes to stop it, even if that involves permanently shutting down the federal government (which is what some of them want anyways)
every year there is a budget count and if you dont pass it . the gvernment shuts down llike every time they do a budget if the senate and all them spend more money which they are doing)than they make then the government shuts down!
Neither side can compromise. This is because Democrats think they win more by the shutdown, and Republicans have to get a concession. So, who wins? The only one thing that will matter in the minds of the American people is which party wins this debate. Most Americans don't care what a filibuster is, they don't understand what a continuing resolution is, they don't understand Congress's power of the purse or where that authority is rooted. They don't care about grand ideological battles wherein the government for the first time in 200 years compels individuals to buy a product from big business. At the end of today, or tomorrow or whenever the shutdown ends, the only thing Americans will care about is who won the debate. Who held strong to their beliefs. Because that party will be deemed the winner. The other party will be deemed the irresponsible trouble-maker. Republicans worry that a shutdown will reflect badly on them. It likely won't, unless they are the loser. Americans like to believe that they believe in grand principals and they like to root for winners, especially underdog winners. So the stakes are set. Let the games continue.
The government has spent all their money the government cannot borrow more money so it has to shut down until they can figure out how to get more money that's basically what it is they borrow and spend borrow and spend now we're 17 trillion dollars in debt