Washington Week (video) | PBS

Donald Trump met with Republican leaders in Washington including House Speaker Paul Ryan to begin to unite the GOP after a contentious primary campaign. Meanwhile Hillary Clinton fights a two-front battle -- fighting off her Democratic challenger Bernie Sanders, who has gotten momentum in late-voting state, while trying to turn her attention the November election and Donald Trump.

On the Webcast, Dan Balz returns from the RNC meeting in Florida to report on Republican preparations for an open convention in July. Plus, Doyle McManus answers the question "What's next for Bernie Sanders and his movement?" as he continues to fight for the Democratic nomination. Carol Lee reports on 28 redacted pages of a September 11 report.

Fresh off his win in New York, Republican front-runner Donald Trump insists he can be "presidential" and is confident he will have the 1,237 delegates needed to avoid a contested convention in July. Meanwhile, the RNC is preparing for all scenarios. In the Democratic race, Bernie Sanders continues his insurgent campaign against Hillary Clinton who holds a considerable lead in the delegate count.

With days until the New York presidential primary, the 2016 race has descended on the Empire State. Democrats Hillary Clinton and Bernie Sanders, who both have New York roots, faced off in their most contentious debate -- arguing about gun control, the minimum wage and Wall Street.

Over 50 world leaders gathered in Washington to discuss nuclear security, but The New York Times' David Sanger calls the meeting more of a "bookend than a success" for the Obama administration. In the 2016 race for the White House, upcoming contests in Wisconsin and New York loom large.

Republican frontrunner Donald Trump was the driving force in the presidential race this week, facing criticism for comments on abortion, foreign policy and nuclear weapons. Will his latest comments slow his momentum ahead of the Wisconsin primary? In the Democratic race, Bernie Sanders and Hillary Clinton traded attacks on campaign financing, trade and abortion.

As Hillary Clinton begins to shift her attention to a general election strategy, Bernie Sanders turns up the attacks on the Democratic frontrunner -- hoping to slow her momentum out of Super Tuesday. Sanders has struggled to win the support of minority voters, and as the race shifts to more industrial Northern states, can he gain their support?

Donald Trump racked up seven wins on Super Tuesday and holds a 100 delegate lead over Ted Cruz which has establishment Republicans worried about his frontrunner status. Joined by 2008 Republican nominee Mitt Romney, Cruz and Marco Rubio have launched sustained attacks of Trump's conservative credentials and record. At times, the Republican race took a decidedly personal -- and anatomical -- turn.

With weeks to go before the first votes are cast in the 2016 election, the Los Angeles Times’ Doyle McManus reports on the rise of anger and harsh language on the campaign trail. He says that the rhetoric used today is the peak of a long-term trend of voter frustration, turned to anger. Republicans, after seven years without control of the White House, are angrier this election than Democrats.

2015 is drawing to a close, and the Washington Week reporters take stock of the biggest surprises of the year. From the rise of Donald Trump to Obama's energy accomplishments to the aftershocks of the the 2008 financial collapse to no government shutdown fights, 2015 has had a lot to remember. Plus, as the newest Star Wars movie is released, the Storm Troopers showed up in at the White House.

As President Obama heads to Hawaii for vacation and looks ahead to his final year in office, Peter Baker of The New York Times reports on what the president has left on his agenda including criminal justice reform. In the 2016 race for the White House, the Bernie Sanders campaign is in hot water with the DNC after a Sanders staffer exploited a security flaw to access Clinton voter records.

Defense Secretary Ash Carter has been serving for less than a year, but he has instituted two major changes at the Pentagon: allowing women to serve in combat and adopting anti-discrimination measures to protect gay and lesbian troops. Gwen Ifill spoke to POLITICO's Michael Crowley who describes Carter as a "creature of the Pentagon" -- someone familiar with building and how to get things done.

Donald Trump may not be TIME's Person of the Year, but behind the scenes video from his photo shoot shows a feisty eagle taking on the GOP frontrunner. Despite some ruffled feathers and Trump's ruffled hair, Trump's campaign loved the shoot and even said of any upcoming photo shoots, "Can we get an elephant?" Meanwhile, the Republican candidates are preparing for their next debate.

Republican frontrunner Donald Trump drove the 2016 presidential debate this week after proposing to ban all Muslims from entering the U.S. A poll released this week showed 57 percent of Americans oppose the plan, and many of his Republican and Democratic opponents have announced their opposition. But Trump's support among Republican voters is only growing as voters appear to like his tough talk.

As U.S. forces continues the fight against ISIS, the Pentagon announced plans to send more special operations forces to Iraq. In neighboring Syria, Bashar al Assad is likely to stay in power for the foreseeable future because, as Michael Crowley reports, the U.S. sees him as "an enemy we can work with."