Ireland had to go to enormous trouble and expense to re-write the constitution and have the changes to the law endorsed by national referendum. The tens of thousands of young women and their children who had gotten in before the changes are still there and unlikely to ever leave.

As far as Portugal is concerned, acquiring Portuguese nationality seems to be fairly easy, even for first generation immigrants. Marriage to Portuguese person after 3 years will do it, or meeting a number of conditions such as:

residam em território português ou sob administração portuguesa, com título válido de autorização de residência, há pelo menos, 6 ou 10 anos…;
conheçam suficientemente a língua portuguesa;
comprovem a existência de uma ligação efectiva à comunidade nacional;
possuam capacidade para reger a sua pessoa e assegurar a sua subsistência; …

As a rule, children born here automatically earn Portuguese nationality, even if both parents are foreign (happened to me.)

Sorry about copy-pasting in Portuguese but I know you’ll understand it…

Regards.

I wonder (because I really do not know) what the Commonwealth benefits are. To what degree is an about movement and residency and how much of it is about citizenship?

I think that the issue about one’s children’s status is key.

It is something to look into.

Most of the Islamist terrorists are Pakistani or Arab Muslims. Arabs in the US are disproportionately Christians; there are very few Arab Muslim communities in which potential terrorists might be bred and hidden. Most American Muslims are either native-born African-Americans or are from South and Southeast Asia (where radical Islam is less established). There are hardly any Pakistani communities in the US.

Meanwhile, the UK has a huge Pakistani immigrant population and it is within those communities that most of the cells have formed or hid. There are also substantial communities from the former British colonies in the Arab world.

Also, on many indicators, Britain’s Muslims are better integrated than America’s. One of the shadow ministers of the Conservative Party is a Muslim, for example. When will the Republicans have one of their leaders a Muslim? And there are several Muslim members of parliament in the UK, and nothing especially controversial about that. It was rather controversial in some quarters here when the first Muslim (native-born and African-American) was elected to Congress just last year.

Are UK immigration laws as strict as you characterize? There is indeed no equivalent to the 14th Amendment. But there is the Commonwealth, and citizens of those countries (which include Pakistan) do have certain privileged access.