So while I will never minimize the costs involved in military action, I am convinced that a failure to act in Libya would have carried a far greater price for America.

There are legitimate concerns and anxieties that the forces of globalisation are leaving too many people behind - and we have to take those concerns seriously and address them. But the answer isn't to turn inward and embrace protectionism. We can't just walk away from trade.

That we are in the midst of crisis is now well understood. Our nation is at war, against a far-reaching network of violence and hatred. Our economy is badly weakened, a consequence of greed and irresponsibility on the part of some, but also our collective failure to make hard choices and prepare the nation for a new age. Homes have been lost; jobs shed; businesses shuttered. Our health care is too costly; our schools fail too many; and each day brings further evidence that the ways we use energy strengthen our adversaries and threaten our planet.

We still have sanctions on Iran for its violations of human rights, for its support of terrorism and for its ballistic missile program. And we will continue to enforce these sanctions vigorously. Iran's recent missile test, for example, was a violation of its international obligations.

What the American people understand is that I look at what we need to get done to keep the American people safe and to move our interests forward, and I make those decisions.

I know many of you are hurting and angry about the economy, and I don't blame you. It's the worst economy since the Great Depression. When consumers can't buy and businesses won't expand for lack of customers, the government has to be the purchaser and employer of last resort. We learned that in the Great Depression, but Republicans obviously didn't - and they've blocked every jobs program I've offered.

Americans coming home, an Iran that has rolled back its nuclear program and accepted unprecedented monitoring of the program -these things are a reminder of what we can achieve when we lead with strength and with wisdom, with courage and resolve and patience. America can do and has done big things when we work together.