In the abundant recent analysis of a nuclearising Iran, scholars and other experts have identified several dangers. The Iranian regime could bully regional rivals, increase its influence in Iraq, further challenge US power in the Gulf and set off a proliferation cascade. Another oft-cited danger is that, protected from retaliation by its nuclear shield, Iran will step up its support for proxy groups in the Middle East. Even without increased backing from Tehran, Hizbullah and Hamas may be emboldened to increase their attacks on Israel, believing that they are covered by an Iranian 'nuclear umbrella'. With a few exceptions, however, most recent analysis fails to explain how Iran would use the bomb to bring about such changes. As outlined by Paul R. Pillar, professor at Georgetown University, most commentary 'links Iran with sundry forms of objectionable behaviour, either real or hypothetical, without explaining what difference the possession of a nuclear weapon would make'. To understand the threats posed by a nuclear-armed Iran, therefore, and to devise policies to avert or mitigate these dangers, we must analyse the causal link between nuclearisation and its potential consequences.
Our purpose here is to examine the contention that an Iranian nuclear umbrella would permit proxy groups to increase their military activities. Acquisition of nuclear weapons could permit Iran to step up its material and ideological support for proxy groups, and embolden regional non-state actors that do not receive Iranian assistance. Although Iran has connections to several proxy groups in the Middle East, we focus on its most prominent relationship: that with Hizbullah. Specifically, we ask how nuclear weapons would change the partnership.