If much of the commentary on the recent announcement of a new Home Affairs portfolio has been misleading, that’s largely because the government has issued only broad statements about its intentions. In the press release announcing the new portfolio, it occupied a mere three of the 26 paragraphs.

The new organisation is a blank canvas: it’s primed, with some tints already on the palette. But the artists are still contemplating the first brushstrokes.

We know that the portfolio will have at its apex a new department that includes parts of the Attorney-General’s Department and the Department of Immigration and Border Protection (DIBP). That new department will act as a ‘portfolio agency’ for ASIO, the AFP, the Australian Border Force (ABF), the Australian Criminal Intelligence Commission (ACIC), AUSTRAC and the Office of Transport Security.

The Cabinet-level minister heading the portfolio will be assisted by two junior ministers—one for security-related matters and the other for immigration. The Attorney-General’s role in oversight of the intelligence agencies will also be enhanced.

The big question, though, is what is it supposed to achieve?

The government’s answer is that the new arrangements will ‘preserve the operational strengths and independence of our frontline agencies, but improve the strategic policy planning and coordination behind them’.

Home Affairs will be the central department that will ‘oversee policy and strategic planning and the coordination of the operational response’ in areas of national security, including counterterrorism and control of serious and organised crime.

Fourteen years ago, the federal government was developing its central role under the Intergovernmental Agreement on Australia’s Counter-Terrorism Arrangements. We argued then that the evolving system was weakest at Cabinet level, where the prime minister and attorney-general carried primary responsibility for policy development and operational activities, respectively.

We pointed out that both would seldom have time to fully discharge those roles. Other national security responsibilities fell outside Cabinet altogether, among junior ministers.

We suggested that the government’s responsibilities in this area should be unified and better coordinated through a minister for homeland security.

We’re pleased that the new Home Affairs portfolio will provide, as Attorney-General Brandis has acknowledged, just such a senior member of Cabinet, who will be able to give 100% of their time to the domestic aspects of national security.

The difficulty will be developing the structure and governance arrangements for the Home Affairs portfolio: in particular, improving the response to terrorism that Prime Minister Turnbull thinks isn’t adequately provided by current ‘ad hoc and incremental adjustments’ to our national security arrangements.

ASIO, the AFP, the ABF, the ACIC and AUSTRAC will remain statutory authorities: they’ll retain authority for their own management, mandated by existing legislation.

Importantly, the prime minister has committed himself to the agencies’ independence and indicated that they will report directly to the Home Affairs minister. That puts paid to the ‘mega-department’ scare that has been thrown around.

All this suggests that the Home Affairs portfolio won’t mirror the creation of the DIBP where existing authorities were absorbed into an existing department.

Whatever shape the new department takes, the portfolio should be served by a networked management system, a realisation of what the prime minister described as ‘a federation’ of border and security agencies.

To produce the unity of strategy, priorities and management in national security policy that’s required, advice to and directions from the minister must reflect the collective positions of the agencies constituting the portfolio.

Establishing a board of senior management to contest and consolidate the views of the minister, the constituent agencies and, potentially, other bodies closely aligned to the government’s objectives in national security would be sensible.

Governance arrangements should support coordination with the dispersed interests encompassed by national security, especially with the states and territories.

While governance arrangements for the portfolio are required to be in place by next July, it’s important that they allow the portfolio to continue to be shaped by the experience of its constituent agencies and provide for flexible development.

One of the government’s objectives is for Home Affairs to improve coordination of operational responses. This implies that the portfolio should contain many of those Commonwealth agencies that would be involved in operational activities.

The initial structure of the portfolio reflects that guidance. Yet the agencies that will be in it don’t cover the full extent of the Commonwealth’s involvement. This includes responsibilities for issues such as recovering from a terrorist attack, safeguarding critical infrastructure, and countering the development of ideologies hostile to Australian society.

Many of the elements covering these functions are in the National Security and Emergency Management Group of the Attorney-General’s Department. There’s good reason to move almost all of them to Home Affairs.

However, functions shouldn’t be passed on automatically. Influencing behavioural change is a delicate task based heavily on trust. Whether this can be maintained if the Attorney-General’s Countering Violent Extremism Centre function is linked to Home Affairs needs careful thought.

Neither should the new portfolio be burdened by legacy decisions. The DIBP is an amalgam of historical reorganisations made over time for a variety of purposes. Transferring it to the new portfolio would have Australia’s national security agency also responsible for functions such as customs tariff classification.

In addition, amalgamating the prime minister’s expectations of preserving operational strengths of frontline agencies with improved policy and coordination, with DIBP’s objective as ‘Australia’s trusted global gateway’ probably doesn’t cut it as a mission statement.

The Howard government moved Customs to the Finance portfolio in 1996. With its security functions now in the ABF, the remaining functions should return to Finance. More surgery could see the non-security functions of Immigration transferred elsewhere, perhaps to the Department of Foreign Affairs and Trade.

The reorganisation of Australia’s national security functions into a single portfolio is long overdue. But improved efficiency won’t happen by itself.

Clear-sighted decision-making and effective implementation will be needed before Home Affairs can be declared a success. At the least, with the decision to establish the portfolio, an important start has been made.