Prime Minister Narendra Modi's ambitions abroad may run the risk of foundering on constraints at home.

By many yardsticks, Prime Minister Narendra Modi's trip to three Indian Ocean island nations -- Mauritius, Seychelles and Sri Lanka -- was a success.

It revealed a focus on the seas to India's south and on maritime security that is forward-looking and welcome.

These countries have ethnic ties to India, and Modi -- as is his wont -- stressed India's cultural connections with the hosts and its soft power.

But there were also a slew of security-related agreements signed.

The problem, however, remains that India's ambitions might be running ahead of its capacities.

In India's southern neighbour of Sri Lanka, Modi's visit came immediately following the remarkable removal by the electorate of the strongman former president Mahinda Rajapaksa.

This means that Modi has more space to manoeuvre.

Rajapaksa -- a man far from popular in Tamil Nadu following his treatment of the Tamils during and after the end of the civil war -- has been replaced by an administration that is more willing to talk about the excesses conducted during that war.

This means that India's message of reconciliation and devolution is more welcome than it otherwise would have been.

Modi made various other promises to Sri Lanka, including the assurance of assistance in developing the island's railways, and the port of Trincomalee.

Meanwhile, in the two other -- much smaller -- nations, the prime minister had a somewhat more unusual agenda.

India signed agreements to build "infrastructure" in two islands -- Agalega in Mauritius and Assumption in Seychelles -- that might turn each of those into Indian "strategic assets".

Agalega, while part of Mauritius, is actually over 1,000 kilometres north of that country.

It is actually a group of two islands, and New Delhi has reportedly wanted the use of the airstrip on the north island for some time.

In Mauritius, the behaviour of Britain and the United States in the takeover of Diego Garcia remains a matter of resentment, so India will do well to avoid provoking similar sentiments.

It is not known how strongly the prime minister conveyed India's eventual intention to close off the "Mauritius route", the loophole in the two countries' tax treaty that is believed to permit the round-tripping of black money.

The problem in many of these cases is that India's ambitions seem to be running ahead of its capacity.

The prime minister may promise assistance to turn Trincomalee into a petroleum hub, but the Sri Lankans will remember that previous attempts to get Indian assistance for development projects foundered on New Delhi's bureaucratic incompetence.

And while the plan to develop strategic assets across India's maritime neighbourhood is solid, where is the money to develop a navy consonant with such ambitions?

The Cabinet Committee on Security recently approved the construction of seven new frigates; but even then, the first of these ships will come as late as five years -- counting from after those currently under construction are finally completed.

Money on defence capital expenditure has been pruned.

This year, the defence ministry spent only Rs 82,000 crore (Rs 820 billion) of the Rs 94,600 crore (Rs 946 billion) it had been allocated for capital expenditure.

For the coming year, the increase in the provision for defence capital expenditure is considered inadequate to meet the country's needs.

Modi's ambitions abroad may run the risk of foundering on constraints at home.