can the caste system remain viable under a modern constitutional liberal democracy?

I don't see how. Democracy is based on equality for all, or at least
the illusion of same --even if [in fact] we struggle with it every
day.

An interesting question.
http://www.indianchild.com/caste_system_in_india.htm
http://en.wikipedia.org/wiki/Indian_caste_system

It is worth noting that the Indian government recognizes the caste
system insofar as it takes steps to integrate the "untouchables"  -
delits, now more often referred to by Gandhi's expression:  Harijans 
= people of God.

The discussion in the first site explains that the system is becoming
looser, although it is still followed in private life to some extent.

Democracy  - one person, one vote -  does not have to eliminate social
and religious distinctions and stratification, but it tends to, I
believe.
Being on the "inside", one often is unaware of such.  Forty years ago
in Europe, religious mixed marriages were the exception, and peopled
married within their own class (but, of course, the chance of meeting
someone from another class socially was limited).  I expect that
education (as in India) is probably a stronger influence than the
government directly, but, again of course, the public educational
system is the result of government policies (so the better-offs and
old names try to send their children to elite schools).

Just a few thoughts on the subject.

I don't think that the "one person, one vote" kind of democracy by
itself does or could do much to end social hierachies such as the
caste system, especially if the more privileged classes or castes are
in the majority. Indeed, it could be argued that western-type
democracy, with governments changing every 4 or 5 years, and
electorates sensitive to any increase in taxation and/or reduction in
their standard of living (in favour of the less well off), is
resulting in the maintenance of an underclass rather than its
elimination.

Long-run, probably not.

Democracy, in its extreme conception, equalizes the political power of
each individual.  While "social power" or something like it does not
necessarily have to be correlated with politcal power, it is unlikely
the social institution of a caste system could withstand a lengthy
experience with one-person-one-vote democracy.

A few instances of a close election coming down to the votes of the
lowest caste, and the consequent pandering to those people would put
significant pressure on the institution.

My best guess - 2 or 3 generations, tops.

-dhouse

the United States had a caste system until the emancipation of the
slaves. The Civil War was fought because the existence of the Peculiar
Insitution was in fact not compatible with the constitutional liberal
democracy created by the founding fathers, who were reluctant,
however, to take on the whole divisive question while trying to
maintain a united front against the British. As for India, the caste
system has survived..though perhaps a bit weakened...more than half a
century of liberal democracy. Maybe it is so woven into the wrap and
wook of Indian culture and Hindu thought that it will always survive
in some form, despite the fact that one would except the huge majority
of lower-caste Indians to get rid of it.

depends how your "castes" are organized. If its based purely on wealth
or religion you have a problem, because typically someones financial
status or religion is voting FOR them rather than the other way around
(if your poor your not going to vote for that huge tax cut for big
buisnesses are you?).
If you organized "castes" based on job, and in turn skill set you
could actually develop a very strong democracy: each caste could vote
directly (rather than representatively) on topics that effected them
or for which they had expertise. The government could in turn
interpret the census of the people to reach conclusions on the topic.
For example: regarding decisions of health and welfare the votes of
doctors and nurses are strongly considered. If it turn is projected to
effect everyone than the entire populace votes while the first group
casts double ballots: one as a citizen a second as an expert. If the
labourer class is the only one effected only they (and experts) vote
etc.
Highly educated people would then possess more decisive power, as they
would have precident to cast more votes on individual topics for which
they had knowledge. While the masses would still have the ability to
represent themselves in every decision that concerned the country as a
whole.

I'll believe in equality when I see people being given equal
opportunity, equal education, and being born with equal fitness.

The sad thing is ... that it does. The caste system remains viable in
India. Would it remain viable in the long term - probably not.

The situation has already substantially improved. But is this due to
democracy: while democracy definitely played a huge role, the improved
economy was a contributory factor. Affirmative action in the form of
reserved seats and positions in university and industry helped. The
fact that what are regarded as the backward castes are the
over-whelmingly larger part of the population too, played its role.
The exposure to and integration with the international community must
have had some effect

It is now nearly 60 years since India became a democracy. Have things
happened fast enough? Certainly not. But then, may be a tradition
that's been around for 3000 to 4000 years is not going to go away in a
hurry. Especially when it has relegious sanction