Ahead of papal visit in Washington, D.C., Vermont Sen. Bernie Sanders is set to join striking federal minimum wage employees demanding $15 an hour. Reuters

Democratic presidential candidate and U.S. Sen. Bernie Sanders is expected to throw his weight behind a labor strike of federal minimum wage workers Tuesday ahead of Pope Francis' visit later that day in Washington. The group organizing the strike, Good Jobs Nation, will receive the support of a rising populist power in the Democratic field as they call on U.S. President Barack Obama to issue an executive order increasing the minimum wage of federal workers to $15 an hour.

Sanders has also introduced legislation to raise the overall federal minimum wage from $7.25 an hour to $15 an hour.

The request from the workers, who are employed in the U.S. Capitol or elsewhere throughout the District of Columbia in federal buildings, aligns closely with policies Sanders has been championing on the campaign trail as he looks for the Democratic nomination. The strike is set to begin at 9:30 a.m. local time, and the workers have planned a march to the Capitol dome, where they are expected to hold a "prayer action" with the hopes that it draws attention to their cause before the visit from the pontiff, who is well known for his sympathy toward the fight against poverty.

The pope's U.S. visit has not been without controversy. His views on progressive issues like climate change, immigration, guns and capitalism, for which he has been a prominent voice, clash with those of many Republicans in Congress. The conflict has resulted in many lawmakers urging the pontiff to steer clear of politically charged messages during his speech to Congress.

Pope Francis is on a several-legged tour of the United States in which he will visit Washington, New York and Philadelphia. While in Washington, the pope is expected to meet with Obama, give an address to a joint meeting of Congress and finally visit St. Patrick's Cathedral, where he will give a blessing and deliver remarks to the homeless there for lunchtime. Francis will then go to New York Thursday afternoon, where he is scheduled to start a series of events that include remarks delivered to the United Nations General Assembly, a visit to a school in Harlem and a mass at Madison Square Garden. He is also set to visit a prison, deliver several masses and visit Independence Hall in Philadelphia.