A hotly contested seat in southeastern Pennsylvania is the main attraction in the state's congressional primaries.
Democratic voters have four choices in Tuesday's balloting for the nomination in the 13th District, which covers parts of Philadelphia and Montgomery County.
The candidates are Dr. Valerie Arkoosh, an anesthesiologist who raised the most money; state Rep. Brendan Boyle, the only Philadelphia resident; state Sen. Daylin Leach, a champion of liberal causes; and Marjorie Margolies, who held the seat two decades ago and is Chelsea Clinton's mother-in-law.
Voter registration in the district is nearly 60 percent Democratic, so the nominee is all guaranteed a two-year term.
The seat is being vacated by U.S. Rep. Allyson Schwartz, who is running for governor.