A news article about Congress planning to buy tanks the Army says it doesn’t want is just one of several stories of the past week that suggest Congress should set spending priorities.

Learning that Congress plans to force a military equipment purchase that the Defense Department does not want is nothing new. For years, similar articles have revealed that the interests of Congress are often more in line with defense contractors than military leaders — or taxpayers. Actual national defense often seems secondary.

The most recent case has Congress planning to spend about half-a-billion dollars to buy tanks the Army says it does not want or need. The Abrams tank, first introduced in the early 1980s, is set to be replaced by a new tank in 2017. Army officials say it’s better to focus on the new tank rather than spend money retrofitting Abrams tanks with flat-panel displays and other upgrades.

General Dynamics, which produces the Abrams, spent about $11 million last year lobbying Congress and employs 700 workers at its Ohio factory.

But the Abrams tank story is not the only case illustrating the need for Congress and the White House to set spending priorities.

In recent weeks, there have been news stories about cancer patients being denied chemotherapy, of children being tossed out of Head Start programs, and of low-income seniors being cut from Meals on Wheels.

These stories are compelling and they are being used by Obama administration officials to show that the sequester, the across-the-board spending constraints, are hurting Americans.

Maybe that’s true. But in the past week, Congress acted quickly in response to flight delays at some major airports caused by the Federal Aviation Administration’s furloughs of air-traffic controllers. The FAA said the furloughs were unavoidable because it had no control over spending cuts. Within days, Congress passed legislation giving the FAA some spending flexibility to keep controllers on the job.

The troubling stories about cancer patients, Head Start children and seniors depending on Meals on Wheels raises questions. Are there no other spending reductions in a $2.7 trillion federal budget that cause less hardship for people?

Congress and the White House so far seem unwilling to set priorities. But that might change with the ongoing budget battle and broad public agreement that borrowing 40 cents of every dollars spent by the federal government is a problem and is unsustainable.

Members of Congress and the White House have for too long thought that every federal program and every tax dollar spent was on a high priority. But not all spending can be a top priority. Congress and the White House have to accept that there are limits to spending — and borrowing — and then set priorities.

That means finding cuts to help higher-priority projects like cancer clinics, Head Start and Meals on Wheels. It also means examining tax exemptions and loopholes, accurately called tax expenditures, in the federal tax code that cost the Treasury about $1 trillion a year.

Congress should give some spending flexibility to other federal agencies, beyond the FAA, to help minimize the harm caused by slowing the growth of federal spending. It’s time for Congress and the White House to demonstrate some leadership and make tough choices. As has been said before, when everything is a priority, nothing is a priority.

When he first ran for president, then-Sen. Barack Obama promised to “go through the federal budget line by line.” He vowed to find programs that were wasteful, duplicated other programs or were simply not effective. Five years later, it doesn’t look like Obama — or Congress, which could do the same thing — has done that.

There must be plenty of savings to be found in a $2.7 trillion budget that can continue chemotherapy for cancer patients, keep poor kids in Head Start and restore any reductions to Meals on Wheels.

Not forcing the Army to buy tanks it does not want would be a good first step. But it would be only a first step.