The easiest way to make a mistake is to tolerate a debate that sells our country short. In recent weeks, politics has reduced an extraordinarily complex country in an extraordinarily complex region and a difficult mission to a simple, headline-ready "yes or no" on troop numbers. That debate is completely at odds with reality. What we need, above all, what our troops deserve – and what we haven't had – is a comprehensive strategy, military and civilian combined.

After eight years of neglecting Afghanistan as Vice President, Dick Cheney has come out of retirement to criticise President Obama for taking the time to examine assumptions before sending troops into war. This from the man who in 2002 told America that, "the Taliban regime is out of business, permanently". I think this is the one time I wish Dick Cheney had been right. But tragically, he wasn't and he isn't today, and that's why we have to make tough choices about Afghanistan now. Make no mistake: because of the gross mishandling of this war by past civilian leadership, there are no great options for its handling today.

One American officer captured our lack of a strategy well when he said: "We haven't been fighting in Afghan-istan for eight years. We've been fighting in Afghanistan for one year, eight times in a row." That is our inheritance.

President Obama began his strategic re-evaluation in March of this year, after he did what he promised to do by sending an additional 21,000 troops to Afghanistan – the most recent of whom just arrived in the country. Now he is wrestling with what comes next, with the knowledge that all options involve real costs and significant risks.

I believe if we redefine our strategy and objectives to focus on what is achievable as well as critical, and empower the Afghans to take control of their own future, that will give us the best chance to succeed. Yes, legitimate questions remain about just what it takes to achieve our goals in Afghanistan. Yes, Afghanistan is but one of a number of pressing national threats, challenges, and priorities. The $243 bn price tag is staggering. And yes, many of our stakes there are indirect. But make no mistake: the costs of failure are very real.

Taken from a speech by the chairman of the Senate Committee on Foreign Relations in Washington on Monday