Students of the `long' McCarthy period in the United States – fromthe late 1940s through the 1950s – have paid inadequate attentionto the effects of this oppressive time upon science. Visa andpassport denials, loyalty oaths, security investigations, andother problems placed in the paths of scientists no doubthindered science. But they also increased the political maturityof its practitioners, a fact of which recent events make usparticularly aware.