Last week, I hiked to the top of Piestewa Peak strolled around Tempe’s Town Lake and enjoyed the desert of the largest municipal park in the country while visiting Phoenix.

We were joined on these trails by folks of all ages, ethnicities, shapes and sizes. There was one guy on Piestewa, a steep hike, with an oxygen tank.

And it was the largesse of government - from the peak renamed in 2010 after the first Native American woman killed in combat to the New Deal that built the trails on South Mountain - that made our recreation possible.

As the race for the GOP nomination gets going for real, it’s time to talk about government’s role in our society.

A grizzly bear roams near Beaver Lake in Yellowstone National Park, Wyoming, Wednesday July 6, 2011. ) (Jim Urquhart/AP)

Rick Santorum, meanwhile, promotes cutting government aid to the poor, and Mitt Romney says he wants to significantly grow the defense budget but isn’t all that clear on how he’d pay for it.

There are important questions that thus far are being addressed in the most superficial and shallow manners. What sort of priority should we place on defense spending? Should taxes be raised for the middle class? For the upper class? For anyone? Should Social Security and Medicare for the elderly continue? Should we regulate our water and air to ensure that it’s clean? Should government provide recreational opportunities and preserve wild spaces such as national parks?

The list of questions goes on and on.

And President Barack Obama is the person who needs to lead the “adult conversation” about government’s role in our lives that politicians seem to be calling for all the time.

Obama needs to talk about what government does right - how it serves real people and provides them with real opportunities. He needs to defend health care reform and offer real examples of how the parts of it already in place are working. He needs to explain how unemployment compensation and, yes, even programs such as food stamps and Medicaid, contribute to our economy and help those who need it.

He also needs to talk about what government shouldn’t be doing. Providing taxpayer cash to private businesses such as Solyndra, the solar-energy company, may be one of those in the latter category.

If he fails to do this, forcefully and often, we all stand to lose.

Sandra Fish teaches journalism at the University of Colorado and has reported on politics in Iowa, Florida and Colorado. Follow her on Twitter: @fishnette