This is a standard refrain of our political discourse, a boilerplate phrase over which we ordinarily have no reason to pause. But (as I describe in Beyond Citizenship) the "rights and obligations of citizenship" have been whittled down to a very small quantity. That reflects and reinforces the diminished meaning of citizenship.
First, on the obligations side, there is a single obligation peculiar to citizenship: jury duty. That's it. Two obligations commonly thought to define citizenship --- military service and taxes --- in fact apply to resident noncitizens as well. Aliens, even undocumented aliens, have to register with the Selective Service. Taxes are extracted largely on the basis of residency, not citizenship (even nonresident noncitizens who have to pay taxes on business interests in the US).
On the rights side, there's only slightly more weight in the citizenship balance. There is the franchise, held out as among the most valuable prerogatives of citizenship. Never mind that about half of voting-age citizens don't bother to cast their ballots. If the vote is thought to equate with political participation, noncitizens have multiple alternative channels to have their voices heard.
For starters, permanent residents can make federal campaign contributions. Noncitizens also have the vehicles of civil society (including powerful churches, unions, and corporations) through which to participate. Many, of course, also have citizen relatives and co-ethnics to advocate their interests through the ordinary political process. And when all else fails, taking to the streets can get the message across pretty effectively, as evidenced by the massive marches in the spring 2006 against proposed immigration reform measures.
There is also eligibility for the federal civil service, which is restricted to citizens (with limited exceptions, including law clerks to federal judges!), and a small number of state public sector positions.
That leaves locational security and some immigration benefits as the most important rights associated with citizenship. If you are a citizen, you are absolutely immune from deportation. As an alien you are less secure. But as a permanent resident alien, you're not that much less secure. Assuming that you stay out of trouble with the criminal law, a green card is the functional equivalent of a passport. That's the salient divide, between legal resident alien and citizen, in considering the meaning of citizenship. But undocumented aliens enjoy a surprisingly level of locational security, too, at least once they're past the border. Interior enforcement is so thin that the average undocumented alien doesn't have much to fear on a day-to-day basis (although admittedly more now than before recent well-publicized raids).
In the book, I chart a historical trajectory in which citizenship has come to mean less over time it terms of what it gives and what it extracts. It was once the case, for instance, that many states restricted land ownership by aliens. Noncitizens were typically barred at the state level from a broad range of professions, including from practicing medicine, accounting, and embalming. Every state in the Union barred aliens from the practice of law. These were significant disabilities that have largely disappeared. On the obligations side, before 1951 aliens could opt out of military service (though at the cost of permanent disbarment from naturalization).
So why not revalue citizenship by infusing the status with a more robust set of rights and responsibilities?
It just won't work. On the rights side, witness the experience with the 1996 welfare reform act, which cut legal immigrants out of important public benefits programs. Within a few years, most of them had been restored. Why? Because there's a general acknowledgment that legal resident aliens are part of the community, too. Another example: even after the foreign influence-peddling scandals of the early Clinton years, proposed legislation to bar contributions from permanent residents went nowhere.
On the obligations side, imagine if you exempted aliens from paying taxes. Who would naturalize at that cost? (To the extent that citizenship does make a significant difference in tax burden — as with US citizens abroad facing estate taxes — it is surely the primary motivation for renunciation.) As for military service, no one really wants to go back to the draft.
That may be the strongest evidence of the diminished condition of citizenship and the state. Dying for your country used to be the paramount obligation of citizenship, what set it apart from other membership organizations, and it was an obligation freely and proudly taken. Today for many the armed forces are a job and not much more (which is by no means to demean those who serve, and those who serve out of patriotism, but judging from recruiting and retention problems they are now a minority). Calls for a return to national service — an important tool for building civic solidarity, as often advocated from the left as the right — have gone nowhere, even in the wake of 9/11 and Iraq. The fact is that most citizens don't feel giving much to their country any more (and most would like to give a lot less, in the form of reduced taxes).
That may be because citizens feel less in common with other citizens. The dynamic then becomes self-reinforcing: to the extent citizenship means less, existing citizens care less about the thresholds to citizenship. But the lower the threshold, the lower the level of commonality, which in turn points towards it meaning less still.