Last week's announcement of the decision by Declan McGonagle to quit his post as director of IMMA doesn't quite draw a line under the acrimonious dispute between himself and the chairperson of the museum's board, Marie Donnelly. The controversy that has raged since last November, when Donnelly informed him of her intention to advertise his position, has been too loud, public and messy to allow such a neat conclusion. But his decision, all the same, does mark the beginning of the end of at least that particular phase of the controversy, and, more significantly perhaps, it opens up the question of IMMA's future role and direction.

Declan McGonagle made his decision after he had achieved what he had claimed all along he had a right to: the offer of another five-year term as director. The announcement of his intention to depart leaves IMMA facing the 10th anniversary of its official opening next month with a bruised and battered board, a jittery staff, an uncertain future and a public perception problem.

The most optimistic prognosis for the institution is that the time taken to advertise the position of director, to find appropriate candidates for the job and to select one of them will allow some if not all of the scars to heal. There are, however, several potential problems attendant on that process.

Firstly, it is entirely possible that some plausible contenders will be deterred by the intense bitterness of the dispute, and by the issue it raises of the role of the board in the running of the museum. Even those critical of McGonagle's style of curatorship were appalled by the publicised account of the manner in which his right to a contract renewal was handled.

Any prospective director will be entitled to ask who exactly runs the museum, the director or the chairperson of the board. The board has to ensure that anyone taking the job can be confident that, while the board may determine policy, the director implements it, with agreed latitude and initiative, and without the threat of undue interference. And, a potentially thorny issue this, the board has, in the meantime, to sort out its priorities in terms of the future direction and policies of the museum.

One of the ironies of the clash between Donnelly in her capacity as chair of the board and McGonagle was that, in terms of their public statements and their track records, their positions on policy seem, on the face of it, remarkably close. When Donnelly implied that the museum had established itself nationally, and now had to make its mark internationally, she seemed oblivious to the fact that one of the most frequently voiced criticisms of IMMA is its lack of attention to its national role, its responsibilities to 20th century Irish art.

There is a considerable public appetite for access to a representative collection of 20th century Irish art that no national institution has yet remotely satisfied and that IMMA, logically, should. To be fair, it must be said that this is something that IMMA, responding to various expressions of public opinion, has been working in recent years to address (energetically encouraging local venues to exhibit works from its collection, for example). The museum might rightly argue that it started life only in the last decade of the 20th century, with limited funding, and the acquisition of such a representative collection was financially beyond its scope.

But the distinctly lacklustre Shifting Ground, IMMA's half-hearted survey show of the last 50 years of Irish art, was a telling indication of how it is not doing at all as much as it could. Equally, the museum's engagement with contemporary Irish art - that is, art by younger artists - while significant, has been frustratingly sporadic and diffuse.

This whole area - from the collection and its display to the attention paid to younger Irish artists - requires urgent attention at IMMA, and is clearly germane to any current policy discussions on the part of the board. Yet, whatever Marie Donnelly is known for in artistic terms, it is not for her interest in Irish art. While she has been involved with both the Tate in London and MOMA in New York, until her quarrel with McGonagle thrust her into the spotlight she was a distinctly marginal presence on the contemporary Irish art scene, something that, arguably, told against her in terms of the glaring lack public support for the position she adopted.

So, while one could be forgiven for forming the impression that McGonagle focused much of his attention - quite reasonably - on the international context, the question arises as to how his concept of international differs from Donnelly's. Presumably the answer is that she has a more mainstream, big-name internationalism in mind. That need not be a bad thing. IMMA needs exhibitions that will raise its public profile and draw in the crowds. There's no reason to assume that it must sell its soul to do that.

Throughout the controversy, the rumour mill was working overtime, and one persistent rumour was that the board's chairperson wanted a young, dynamic director from abroad in the job, someone who would regard IMMA as a stepping stone, would come in, put it on the map with a series of high-profile exhibitions, and move on. This game plan might suggest that Irish art would be sidelined - but, again, there is no reason why that should be so. Any good museum professional taking the reins of a national institution will know that they must look to the national as well as the international context. Of course, given the level of controversy, it remains to be seen whether anyone fitting that description applies for the job.