The US federal government is heading toward a shutdown that will disrupt many services, squeeze workers and roil politics as Republicans in the House, fuelled by hard-right demands for deep cuts, force a confrontation over federal spending.While some US government entities will be exempt — Social Security checks, for example, will still go out — other functions will be severely curtailed. Federal agencies will stop all actions deemed non-essential, and millions of federal employees, including members of the military, won't receive paychecks.Here's a look at what's ahead...