When picking a fight with someone smaller than you, you have to make sure that you win.
From the early minutes of last night’s BBC debate, Martin McGuinness was openly gunning for his Foyle rival Colum Eastwood – as he had done in the UTV leaders debate at the start of the campaign.
Unfortunately for Mr McGuinness, last night he only managed to emerge with what was at best a score draw.
Given Sinn Fein’s leviathan-like dominance of northern nationalism and particularly given his own decades of experience compared to the youth and inexperience of Mr Eastwood, it is the older politician who emerges weaker.
He set out to squash the SDLP leader but failed to do so.
Although there were testy exchanges between Mike Nesbitt and Arlene Foster, it was the smaller leader, Mr Nesbitt, who was most aggressively pressing his rival, with Mrs Foster adopting a largely defensive approach.
David Ford did little wrong, but, as often in these situations, struggled to have his voice heard between the intra-unionist and intra-nationalist bouts.
Perhaps the most content politicians after last night’s dull debate will be in the smaller parties who might hope to pick up a protest vote.