Gas is at $4 a gallon and global warming is melting the polar ice cap. The United States should be racing to create cleaner, more secure energy sources. But Congress has spent a year bickering over what should be a no-brainer: continuing tax credits for renewable energy.

The House last week passed legislation to renew incentives for producing and investing in solar, wind and other forms of clean energy. But prospects are dicey in the Senate, and the oil-centric White House already has threatened a veto.

It's time for the president and Senate Republicans to face up to energy and economic realities by agreeing to renew the credits that otherwise will expire at the end of the year. If they don't, they will squander the early progress on alternative energy inspired by the credits, and they'll blow an opportunity to do something smart to help future generations.

San Jose Mercury News, May 27

Digging on two planets At a time when gardeners all over the Northern Hemisphere are hunching over and digging into Earth's surface, the 7.7-foot robotic arm on the lander Phoenix will soon be digging into Mars. Earth's diggers are coaxing along a new season of plant life; NASA's Phoenix will attempt to answer the most basic questions of whether life might have ever existed on the Red Planet. This $420 million unmanned mission -- superbly executed so far -- should provide invaluable information at a fraction of the cost of manned missions into space.

Scientists steered Phoenix to a landing near the north pole of Mars on the hunch that, while the planet's surface is now too cold for life, the north pole might have once been tipped during summer toward the sun. This could have melted into water the ice that an earlier orbiter had detected. ...

Phoenix will now have three months to provide data about Mars' past and current chemical components. It is ironic that an inanimate object will be making the quest for signs of life. But doing so will spare taxpayers a small fortune -- and strike a chord with gardeners nursing sore backs.

BOSTON GLOBE, MAY 28

Iran and the inspectors Amid all of the White House's saber-rattling, it is tempting to discount Iran's genuine misbehavior. The latest report from the International Atomic Energy Agency is a grim reminder that Tehran is pressing ahead with its nuclear program, and the United States and its allies don't have a strategy for containing it. ...

The United States and the other major powers -- Russia, China, Britain, France and Germany -- have yet to put together a serious package of incentives and sanctions that might persuade Iran to change course.

That must include a credible American offer of security guarantees and normalized relations if Tehran abandons any nuclear weapons ambitions. If Iran persists, it must face sanctions with a lot more bite than Russia and China have been willing to consider, including a broader ban on doing business with Iranian banks and bans on arms sales and new investments in Iran.

New York Times, May 28