If you listen to the US government, drugs are bad — end of story. That shallow drag on a passing joint will launch you on a slippery slope towards social exclusion, jail and general misery. But if you listen to scientists instead, your outlook on drugs may be more nuanced. Not everyone becomes addicted, and exactly how drugs such as marijuana and ecstasy affect the brain over time, for example, are questions that only painstaking research can resolve.

In a rather uncomfortable spot between these two standpoints sits the US National Institute on Drug Abuse (NIDA) — tasked by Congress with providing the science that guides drug treatment and prevention, and under heavy pressure from its political paymasters to reinforce their war on drugs. Many critics say the agency's research agenda has occasionally been biased as a result (see page 394).

It takes a strong leader to maintain the integrity of research in the face of such political pressure. Nora Volkow, the agency's director, radiates passion about science — and asserts that experiments, not politics, will guide her decisions.

A report last week from the Union of Concerned Scientists discusses the case of a researcher who, when being considered for a position on NIDA's advisory council, was questioned by a White House staffer about whether she supported “faith-based” drug treatment programmes, or voted for President Bush. This and other examples illustrate how the influence of politics has made itself felt in NIDA, and the tough task that Volkow faces to keep the agency clean.

NIDA's goal is to figure out the risks posed by drugs and how best to help those who suffer from taking them. It is not to reinforce politicians' ideas that we should lock up those who try drugs. When it comes to politics, NIDA should just say no.