Why Are So Few U.S. Women in Politics?

“The rules of the game are set up to the advantage of the dominant majority bloc, which is not just Democrat or Republican but is wealthy white males,” said Andrew Reynolds, a professor at the University of North Carolina.

The Republican debate sure proves this point. Not only were all the candidates white men, so were the three questioners. OK, forget black or brown. They couldn't find one woman to ask questions?

The United States is on the latter track but lags many of its European counterparts. Only 16 percent of lawmakers in the U.S. Congress are women. Compared to countries of similar wealth, one would expect 30 to 50 percent, Reynolds said.

The U.S. political structure is partly responsible. Many parliamentary systems encourage alternative voices by allowing small parties, but the United States fosters a two-party system in which the parties have to appeal to a broader audience.

Women have more difficulty being elected in presidential systems. Historically, some 69 percent of women leaders have been prime ministers with only 31 percent from presidential systems, said Ann Gordon, a political scientist who co-edited the book “Anticipating Madame President.”

It’s a piece of the puzzle, she said, but she sees greater challenges.

“The single biggest obstacle in this country is that voters are uncomfortable with the idea of a woman who is commander in chief,” Gordon said. “That’s due to gender stereotypes.”

Susan Carroll, a senior scholar at the Center for American Women and Politics, said women seeking the presidency still had to address the perception that they were less able than men to deal with military issues and international crises.

Clinton, a New York Democrat, has tried to address the issue by sitting on the Senate Armed Services Committee and taking a strong stance on terrorism during debates, Carroll said.

It also may be a factor in Clinton’s refusal to apologize for her Iraq war vote, an issue that has caused her difficulty among many Democratic constituents, Carroll said.

“I don’t think Hillary Clinton has the options that other candidates have,” she said. “She cannot for a moment appear to be weak on defense or admit to any kind of failing like that.”