In their first joint television interview since the 2012 presidential campaign, Mitt Romney and Rep. Paul Ryan (R-WI) joined Megyn on “The Kelly File” tonight for an exclusive interview to discuss the state of the Republican party and the country.

Romney took aim at President Obama's foreign policy, saying that the president's errors, such as not leaving forces in Iraq and failing to take earlier action in Syria, have endangered the U.S. against the growing threat of ISIS.

“The president has a foreign policy which has failed once again," Romney said. "He underestimated the extent of the threat represented by terror in the world, and specifically ISIS. And as a result, now we find ourselves facing a series of severe and horrific scenes on the world stage.”

Megyn played a clip from a 2012 debate in which Obama mocked Romney for saying Russia was the United States' greatest geopolitical threat.

Romney said that one of Obama's major foreign policy errors was underestimating Russian President Vladimir Putin and confusing geopolitical foe with direct threat.

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Ryan, author of the new book "The Way Forward," said he isn't happy with the direction the country is headed and wrote his book to show how to unify the conservative movement and fix the country's problems before it's too late.

He said Republicans need to state not just what they are against, but what they are for, and that was his purpose in writing the book.

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Romney was also asked about the situation in Ferguson, Missouri, and said the federal government's extraordinary response has been appropriate to give people the confidence that justice will run its course.

Watch the clip above.