White House Chief of Staff Bill Daley is stepping down. He's held the position for about a year. Jack Lew, the director of the Office of Management and Budget will replace Daley. Melissa Block talks to NPR's Scott Horsley for more.

The justices tried to untangle a three-court knot. The case tests the allocation of four new congressional seats that were created largely because of that state's booming Latino population. But it could have nationwide repercussions.

A checklist used during the failed 1970 Apollo 13 moon mission is creating a problem for NASA. Commander James Lovell's checklist, which was instrumental in getting the crew back to Earth successfully after a technical failure in space, was recently sold at auction for almost $400,000. Now, NASA says that Lovell didn't have the right to sell the checklist. Audie Cornish speaks with Robert Pearlman, editor of the website CollectSpace.com, about the dustup.

Melissa Block interviews Jim McCormac, a biologist with Ohio's Division of Wildlife, about why snowy owls are being sighted farther south in the United States than in previous years. He says most years, there are two to four of them sighted, but there have already been 15 sighted in Ohio since mid-December. He talks about his theory of why this is happening.

Former Pennsylvania Sen. Rick Santorum fell eight votes short of defeating former Massachusetts Gov. Mitt Romney in Iowa last week. But he is nowhere near matching Romney in New Hampshire. A look at why Santorum's surge seems to be skipping New Hampshire — and why it may come back in South Carolina.

Despite the lukewarm way most Republicans respond to Mitt Romney in the Granite State, no one challenger has emerged to capitalize on the dissatisfaction.

New Hampshire voters will either catapult Mitt Romney securely onto the path to the Republican presidential nomination or undercut the air of inevitability surrounding his campaign. The former Massachusetts governor has been anticipating a catapult. But Monday, he stumbled.

The U.S. Department of the Interior is placing a 20-year moratorium on new mining claims in and around the Grand Canyon. Environmentalists say the ban is crucial to protecting the region. However, the mining industry and some Republicans say the moratorium will be harmful to Arizona's economy and the nation's energy independence.