Hillary Clinton writes in a new book that she is "proud" of what she accomplished as secretary of state.
Clinton's book, Hard Choices, comes out June 10, as speculation grows about her potential run for president in 2016.
In the author's note, released Tuesday, Clinton acknowledges she wishes she could "go back and revisit certain choices" from her time as the United States' top diplomat.
But she says the government "needed to do better" after the 2001 terrorist attacks, the Iraq and Afghan wars and the economic recession, and she believes it did.
Critics have characterized Clinton's four years at the State Department as lacking major achievements. Republicans have also questioned her handling of the September 11, 2012, terrorist attack that killed the U.S. ambassador and three other Americans in the Libyan city of Benghazi.
In her author's note, Clinton says she has listened to both her "heart" and "head" in making the big decisions of her life.
The former Democratic U.S. senator and first lady says she wrote Hard Choices, which focuses on her time at the State Department, for "Americans and people everywhere who are trying to make sense of this rapidly changing world" and for "anyone anywhere who wonders whether the United States still has what it takes to lead."
Clinton says for her, "the answer is a resounding 'Yes.'" She writes, "Talk of America's decline has become commonplace, but my faith in our future has never been greater. While there are few problems in today's world that the United States can solve alone, there are even fewer that can be solved without the United States."
She adds that everything she has done and seen has convinced her that "America remains the 'indispensable nation.'"
Once her memoir is released, Clinton will embark on a tour to promote it, visiting cities throughout the U.S. and Canada.