Americans ought to be very clear on why some sectors of the federal government “shut down” Tuesday morning. The bottom line is simple: President Barack Obama and Senate Majority Leader Harry Reid refused to grant millions of people the same breaks the administration already has handed to big businesses, scores of labor unions and others favored by the current administration.

It really is that simple.

Officially, Reid and other liberals in the Senate rejected a plan to provide money for the government. They did so because the bill, initiated by conservatives in the House of Representatives, also called for a one-year delay in enforcing Obamacare, the national health insurance takeover.

Obama blasted House conservatives, accusing them of not doing their jobs “just because there’s a law that (they) dont like.”

Really?

The law of the land, as the president is so fond of referring to Obamacare, was enacted three years ago. In plain language, it requires all Americans to have government-approved health insurance or pay stiff new taxes for refusing to do so.

Obamacare also requires all employers with 50 people or more on their payrolls to offer insurance to those working 30 hours a week or more.

This summer Obama declared big businesses will be given a one-year delay – the same amount of time conservatives sought for the rest of us – in complying.

In addition, hundreds of organizations, companies, government entities and labor unions have been given waivers from compliance with Obamacare. Scores of unions, with an estimated 543,000 employees, will not have to offer insurance.

Apparently conservatives in Congress are not permitted to suggest altering Obamacare formally and legally – but the president himself is allowed to make changes unilaterally if he doesn’t like the law.

So, beginning Jan. 1, most Americans will have to obey Obamacare’s mandates or pay higher taxes from which millions of others have been exempted.

If you are a small business owner, that will not be easy. The government’s Obamacare website, www.healthcare.gov, was supposed to allow small business people to enroll for insurance beginning Tuesday. The system will not be ready until sometime in November.

One of the authors of Obamacare, U.S. Sen. Max Baucus, D-Mont., now terms the law a “train wreck.”

Obama has chosen to circumvent the law to protect a few million of the favored from it. But when conservatives in the House suggested basic fairness dictated giving everyone the same break, the president and Reid said no.

That, and that alone, is why part of government was “shut down” Tuesday.

Incidentally, bureaucrats handling Obamacare remained on the job.