U.S. presidents have guided us to wartime victory and plunged us into economic depression. All of their triumphs and failures can teach us a thing or two about our own careers. Here are some important lessons we can learn from our former U.S. leaders:

"The only thing we have to fear is fear itself."
When Franklin D. Roosevelt uttered these words at his first inaugural address in 1933, the country was at the height of the Great Depression. His risky moves pulled the nation out of economic crisis and provided strong leadership during wartime. Being afraid to take risks can keep you from advancing your own career. Apply to that job you think you think you're not qualified for. Propose that unusual plan to your boss. And most importantly, don't let fear of rejection or change keep you from the career of your dreams.

Be flexible and open to change.
The Civil War was a turning point in American history, and knowing this, Abraham Lincoln adjusted the presidential role to fit the times by expanding the military, freeing slaves and spending more money. Sure, he met with criticism, but he told Congress, "As our case is new, so we must think anew, and act anew."

Lincoln's ability to react to the changing times made him widely hailed as one of the greatest presidents in history. By taking classes, undergoing additional training and staying aware of current events, you can be more prepared for new advances in technology and developments in business models.

Keep your nose clean.
The Enron crew and Martha Stewart might be facing different career prospects if they had taken a lesson from Richard Nixon. Similar to recent corporate scandals, an investigation into a 1972 break-in of the Democratic National Committee offices at the Watergate complex slowly implicated government staff -- eventually reaching the very top. Expecting impeachment, Nixon resigned his post -- and the Watergate scandal will forever haunt his legacy. Slip-ups and missteps can cost you your job and taint your professional reputation for years to come.

Learn from your mistakes.
All presidents made some mistakes -- some of them huge. What separated the most successful presidents was their ability to learn from their errors, own up to them and then move on. Take John F. Kennedy: Shortly after his inauguration, Kennedy approved an invasion into Cuba to topple dictator Fidel Castro. The Bay of Pigs invasion was a dismal failure, embarrassing the Kennedy administration. But instead of letting the mortification ruin his career, he simply assumed responsibility -- and Americans respected him for it.

Be wary of office romance.
If you think you can keep your office fling quiet, remember two words: Monica Lewinsky. After rumors of Bill Clinton's extramarital affair with a young White House intern exploded into national news, the president had to protect more than just his marriage -- he had to defend his job from impeachment. If the president can get caught, so can you.

Stand out from the pack.
Can you list the accomplishments of President Chester Arthur? You're not alone. A Web site dedicated to Arthur, John Tyler and James Polk hails them as the "forgotten presidents." In contrast, the accomplishments of George Washington, Abraham Lincoln and Franklin D. Roosevelt are permanently etched into Americans' memories (and history books).

What separates the remembered presidents? They weren't afraid to take a stand and change things in our country. Don't be content with mediocrity in your career. Flaunt your greatness, and leave a legacy!

Then there is our current President, George W. Bush. The only thing we can learn from him is if you mislead the American People with distorted facts, they will see right through that and turn on you. Maybe he is the one that needs to learn a lesson from us.