Editors note: You can hear The Public Philosopher on Radio 4 at 9am on 23 and 30 Oct and 6 Nov 2012. Here, Mukul Devichand who worked on the programme with Professor Sandel talks about the issues raised in the first programme. PMcD

If you think Texans attitude towards illegal immigrants is simple - lock 'em up and shut the borders - the first programme in a new series of Radio 4's The Public Philosopher may surprise you.

With the US presidential vote around the corner, we took Harvard political philosopher Prof Michael Sandel to the University of Dallas in Irving, Texas to ask a public audience: how far should an open society go in accepting outsiders?

In other words, what's the moral case for and against immigration, and to what extent should illegal immigrants be punished?

These are tough issues in Britain but in Texas, which borders Mexico, the issue has a unique resonance.

Over a million "undocumented" people, who have crossed the US border illegally, live in the state and across the United States there are an estimated 11.5 million such people - many from Latin America.

That led us to the first moral issue addressed in the programme: now that they are in the USA, what should be done about this huge population living in the shadow of the law?

In particular, what is the right moral attitude towards the children of illegal immigrants, who were brought to America when they were very young?

Some argued that it was their parents, not them, who broke the law - so does that give them a moral right to become US citizens?

One passionate speaker told Prof Sandel it was a double standard for other law abiding Americans to have to tolerate illegal acts - even if the children were not to blame. Then, she revealed that she herself was a (legal) immigrant.

But another young woman - herself the child of an "undocumented" worker - said that her own hard work and contribution to American society gave her a moral right to citizenship.

The future for the children of illegal immigrants is a hot political issue in the US election. The scale of the issue - and the fact that Hispanic Americans are an increasingly important source of votes - meant Barack Obama and Mitt Romney offered their own solutions in their second televised debate last week.

But our approach in this programme was different because it addressed morality, as well as politics. In turn, Prof Sandel encouraged the audience to pull back and ask some difficult, prior, questions:

• Is it morally legitimate to have any border controls at all?
• If yes, should they be based on economics - on the skills a country needs - or an idea of shared citizenship, culture and values?
• If immigration policy is dictated by economics alone, what does that tell us about the political community we create?

Immigration, argues Professor Sandel, is so passionately debated precisely because it lays bare our idea of citizenship political community.

Therefore, to form a view, Americans - and anyone else debating immigration - have to ask what values they, as a nation, really stand for?

Mukul Devichand is a Senior Broadcast Journalist in News and Current Affairs, Radio

• Listen again to The Public Philosopher immigration debate
• Download the programme
• Listen to the archive, featuring debates about health, wealth and education:
• Listen to Prof Michael Sandel's 2009 BBC Reith Lectures: A New Citizenship