David Trimble's manner and gait give the impression of a man living on the edge, which in essence is where he has been politically for the past four years in his efforts to modernise Ulster Unionism.
While he initially strongly opposed the peace process, the IRA and loyalist ceasefires it produced led him to conclude that Unionism had no choice but to engage with it and Tony Blair's government.
Yet although this eventually led him to the post of Northern Ireland's First Minister in the new political dispensation, he has often been prepared to put his own job at risk, thus causing uncertainty and annoyance among republicans and hardline Unionists.
His strategy has been to place the arms decommissioning question at centre-stage, elevating the issue to the point where the survival of the new system becomes dependent on republican delivery.
This was first seen throughout 1999 with his declared policy of "no guns, no govern-ment". It meant that although the new Belfast Assembly and other institutions were in place, power was not devolved to them because of the insistence on prior IRA decommissioning.
At the end of that year Mr Trimble changed his line, saying the new government could come into being without IRA guns up-front. At the same time, however, he lodged a postdated letter of resignation, to come into effect within a few months unless the IRA had decommissioned.
When the IRA did not do so Mr Trimble was on the point of resignation when – as he had hoped – the Government suspended the Assembly and other institutions after just 72 days in operation.
A few months later the institutions were reinstated after substantial movement on the part of the IRA, which promised to put its weapons beyond use in certain circumstances, and in the meantime allowed several of its arms dumps to be inspected by international observers.
In tendering his resignation this time, Mr Trimble clearly had this previous experience in mind. He believes that the IRA moves only under maximum pressure, and is hoping that it will do so again when it is faced with a threat to the Agreement's survival.
At the same time as these recurring confrontations with republicans, the Ulster Unionist leader has had regular trials of strength with Unionist opponents both inside and outside his own party.
His party's regulations allow for frequent meetings of its ruling council, where he has received regular buffetings. He has generally got his policies through, although ominously by smaller margins each time.
Last year he fended off a leadership challenger who took 43 per cent of the vote, while more recently he won a policy vote by just 53 per cent to 47 per cent. The Ulster Unionist Party's poor performance in the general election showed that he was not a vote-winner among the Protestant grass roots.
As all this indicates, he has had a precarious hold on power in two different senses. Within his party his opponents are forever lurking in the background waiting for another chance to strike. In terms of the devolved government, he has resorted to actual or threatened resignation with the aim of forcing IRA disarmament.
He would contend that while he has occasioned the present crisis its actual cause is not his behaviour but the continuing lack of IRA decommissioning. His return to office now depends on the IRA responding to his action and going further than it ever has before.Reuse content