There is an unseemly precision to the numbers that senators have been batting around in three days of immigration hearings in Washington this week. Immigrants now in the US illegally could end up waiting 13 years to become citizens. That seems a long time, since most of those without papers have already been in America for more than a decade. They would also owe a $2,000 fine. That seems low, since over a decade it comes to roughly the cost of a speeding ticket each year.

The Senate’s 844-page immigration reform bill aims to regularise migration by fixing prices for it. The value of immigrants to the US, the value of citizenship to an immigrant?.?.?.?these have always been discussed as wispy abstractions. Now senators are, in effect, asking: “What am I bid for this passport?”

We know there is a monetary value to western citizenship because many countries sell it outright. Some rent residency, too. You can reportedly acquire citizenship in St Kitts for $250,000. Grenada is starting a similar scheme. Britain, the US and Canada all use offers of residency to lure investment, although in times of recession these can be a political embarrassment. Canada stopped accepting applications for its immigrant investor programme last year, pleading a bureaucratic backlog.