[Galadriel55]

I feel that Cirion's choice to give away Calenardhon is only immoral if you consider Gondor's ancient borders as something sacred or set in stone, something that cannot be changed. But what's in a border? What use are the old borders to a country that's shrunken to a third - if not less - of its size? Gondor already gave up most of its land, in fact if not in law. They old borders mean something in their tradition - Boromir's horn is supposed to be heard anywhere inside the old boundaries, and Faramir gives Frodo leave to pass on old Gondorian lands that really aren't in their control anymore. But the reality is that Gondor lives on a fraction of its former land, and land without inhabitants cannot be claimed by said inhabitants. The old boundaries mean something in tradition, but they are a relic that did not reflect the newer times - and will not reflect Aragorn's times either since it seems like his realm would be much wider and possibly eventually include all lands west of Rhun. So is there anything inherently unchangeable about Gondor's borders?

If the issue in question is not in the borders themselves but in Cirion - that it was not within his rights to give away land that was not his - I would argue against that for two reasons. First, the Stewards are not supposed to preserve Gondor in a cocoon and prevent any change, to keep it exactly as it was in the days of the king. They are supposed to rule Gondor as a king would rule it, and to rule it in its best interests. Best interests don't always include territorial expansion. Secondly, I see the gift not as giving away land, but as gaining an ally. Gondor could not populate Calenardhon. The land is or will soon be lost anyways. But the oath Cirion and Eorl gave makes Rohan an eternal friend to Gondor. So yes, the land is given to a new set of inhabitants, but if you think about is in terms of political alignment rather than race Cirion actually made Gondor stronger. Where it used to have the power of one nation, it now has two, and someone to cover their back. The land is still serving Gondor's prosperity even under the complete control of the Rohirrim by nature of their oath. It's not really a gift, and it's not a lease, but it's something in between that hangs on the good faith of the rulers of both countries.