WAMU-FM: WAMU: The Diane Rehm Show Podcast

A billion dollars here, a billion dollars there, and you've got a record presidential election. The U.S. Supreme Court decision in Citizens United has unleashed a flood of big money in the 2012 campaign from wealthy individuals and others. The new breed of Super PACs played a major role in the Republican primary fight. Now, in the general election, they are helping to finance the most intensive early barrage of TV advertising in history — and the most negative one. For the first time, an incumbent president and his allies might be outspent by his challenger. We explore the battle for bucks in the contest between President Barack Obama and presumptive Republican nominee Mitt Romney. Who's spending what — and whether it makes a difference.

Shawn Colvin began life on the South Dakota prairie where the great sky was a canvas on which to paint her dreams. Her father gave her a guitar at age 10 and she has been pursuing a music career ever since. In 1989, her debut recording won a Grammy for Best Contemporary Folk Album. Nine years later, she won two Grammys for the hit song "Sunny Came Home." But she battled alcoholism, depression and bad choices in love along the road to success. In a new memoir, she describes how she found her voice as a songwriter — and why she thinks she's a lousy girlfriend and an even worse wife.

In Ohio, the strip of grass between the sidewalk and the curb is called a "tree lawn." In other parts of the country, it is a "curb," a "devil's strip," a "parkway," a "swale," or a "street lawn." More than a dozen names for this can be found in the Dictionary of American Regional English. The fifth volume covers words and phrases from "slab" to "zydeco," and completes a 50-year project to capture the unique ways people in different parts of the country speak. The dictionary has been used to solve crimes, teach medical students, train actors and understand political candidates. Joan Hall, chief editor of the dictionary, and linguist Ben Zimmer join Diane to discuss the diversity of American language.

In this month's environmental outlook, a look at rising sea levels and what's at stake. Whether it's caused by natural variability or human activity, the fact remains that sea levels are rising. The U.S. Geological Survey recently estimated that the Eastern Seaboard — coined a "hotspot" by scientists — will rise to four feet by 2100. A separate study by the National Research Council says ocean levels on the California coast could rise by three feet by the end of the century. Diane and her guests look at the causes and consequences of rising sea levels.

Stockton, Calif., is the largest U.S. city to declare bankruptcy, and others could follow. A panel joins Diane to discuss economic pressures on local governments and the push for privatizing public services.

Mexicans went to the polls yesterday to choose a new president. The official preliminary vote count handed a victory to Enrique Pena Nieto. A win for the former governor of the state of Mexico marks a return to power for the Institutional Revolutionary Party. Known as the PRI, it controlled Mexico's presidency for more than 70 years until the election of Vicente Fox in 2000. Some fear the PRI's re-emergence will bring a return of corruption and patronage to national politics. Issues facing the new president include a continuing drug war and sputtering economy. Diane and her guests discuss the outcome of the Mexico presidential election.