With U.S. Sen.

Bernie Sanders (I-Vt.) entering the race for the Democratic presidential nomination against Hillary Clinton, he may offer disgruntled liberals and Democrats an alternative voice.

In 2008, U.S. Sen. Barack Obama tripped up Clinton by offering a unique blend of youth, liberalism, and outsider appeal. The Illinois senator was able to credibly assail Clinton on her support for the Patriot Act and the Iraq war. Although a tougher feat for Sanders to replicate, could the Vermonter pose trouble for Clinton on the foreign policy and civil liberty fronts as well?

Sanders has generally supported less intensive and polarizing military maneuvers, such as the 1999 bombing campaign of Yugoslavia and the 2001 invasion of Afghanistan, and avoids the label of an all-around peacenik. Though unlike Clinton, he has opposed the larger, more unpopular wars, including the 2003 invasion of Iraq.

Sanders was also relatively cool on President Obama's 2011 intervention in the Libyan civil war that was promoted by the Clinton State Department. Dismissing the administration's claim that it was "not engaged in a military-driven regime change," Sanders retorted, "I think when somebody drops bombs on other people, usually I think we refer to that as a war."

He continued:

"I think one of the things many people are upset about is this war took place without consultation of the Congress, without debate within the Congress. . . . but I think in the midst of two wars, I'm not quite sure we need a third war, and I hope the president tells us that our troops will be leaving there, that our military action in Libya will be ending very, very shortly."

Sanders has also been more forthcoming on NSA reforms and surveillance than his rival. Clinton, coy about what reforms to NSA surveillance she would institute, says she favors "balancing civil liberties and security." While admitting that Edward Snowden is guilty of violating the oath he took upon employment, Sanders conceded that the former NSA contractor and leaker performed services by exposing the surveillance practices of the agency:

"The interests of justice would be best served if our government granted him some form of clemency or a plea agreement that would spare him a long prison sentence or permanent exile from the country whose freedoms he cared about enough about to risk his own freedom."

Despite some ideological advantages, the 73-year-old Sanders may not pose the same threat to Clinton that Obama did in 2007-08. Unlike Obama, Sanders has a lengthier voting record that may make him vulnerable among party liberals looking for an alternative.

As a House member, Sanders voted against the first iteration of the Patriot Act and the creation of the Department of Homeland Security. Though he has since voted for their retentions, he also voted for appropriations for the Iraq War -- a war he opposed. The script for unseating former secretary of state Hillary Clinton may be available, but it is questionable whether Bernie Sanders is the one who can win with it.