Rarely have two US presidential front-runners needed more from running mates than Hillary Clinton and Donald Trump. The Democratic and Republican leaders in the 2016 White House race are unusually unpopular nationally, polls show, despite their success with voters in their respective parties. Clinton has struggled to generate excitement about her candidacy and assuage voter concerns about her trustworthiness, while Trump fares badly among women and minorities in polls.
Their weaknesses only increase the importance of their vice presidential pick, who could potentially help them rally support in key demographics ahead of the November 8 vote - if each gets their party's nomination. Hispanic advocacy groups are lobbying Clinton to choose a Hispanic running mate. The person most often mentioned - Julian Castro, the housing and urban development secretary who is one of the party's rising stars - is opposed by liberal activists who accuse him of favouring Wall Street firms in the sale of distressed mortgages.
Some of the groups have started an online petition against Castro's candidacy, which has angered the Latino Victory Fund, a non-partisan advocacy group that has been pushing for a Latino vice-presidential nominee. "These attacks against Secretary Castro are completely unfounded, short sighted, and only serve to pit us against each other," said Cristobal Alex, the fund's president. The US Hispanic Chamber of Commerce has called on Clinton to choose Castro.
Democratic strategist Joe Velasquez, a Clinton supporter, said a Hispanic running mate could make a difference in swing states like Florida, Colorado, Nevada and Virginia, which have large Hispanic populations. Polls show Hispanic voters overwhelmingly dislike Trump, in part because of his comments likening illegal immigrants to criminals. US Labor Secretary Tom Perez has also been mentioned as a possible Latino pick.
But Clinton's decision isn't clear-cut. Given Trump's unpopularity with some moderate Republicans, she may want a vice-president who can wrest away some of those voters. Someone like Tim Kaine, a senator from Virginia who personally opposes abortion, or New Jersey Senator Cory Booker, who has close ties to the financial sector. There was no immediate comment from Castro, Kaine, Perez or Booker.
Clinton though could give a higher priority to winning over liberal democrats, who see her as too pro-Wall Street and have flocked to her rival, Senator Bernie Sanders of Vermont. Sherrod Brown, a senator from Ohio who is a fierce opponent of global trade deals, and Senator Elizabeth Warren of Massachusetts, a fierce critic of the banking industry, have both been named as possible vice president picks. Brown and Warren did not respond to requests for comment. Democratic strategist Chris Kofinis is skeptical that Clinton needs to spend much time appeasing the liberal wing of her party if she wins the nomination.