The original poster asked specifically about a genetically identifiable group i.e. white, rather than about what appears on ones passport i.e. nationality. Reading the replies it is clear that many here do not identify themselves particularly closely with their genetic ancestry. It is not, to be fair, an approved thing to do in modern society so this is not surprising. However, there are people who do identify with their ancestral roots and do care about its status within the world. It is really just a matter of personal preference and choice.
Those that want to preserve their racial heritage know that it is easier to achieve if their citizenry is segregated from other populations in the world, hence they are less likely to welcome high, or even any, immigration. However, any given society is made up of liberals and conservatives and the decision about border control in a democratic society is determined by the concerns of the majority.
Since the conservatives do not command the majority in this country they are not able to segregate communities as they would like. Some people in the past have achieved segregation of groups by force but even if this was achievable - and in my view it is not - the resultant community is inclined to deteriorate genetically because the more ambitious and intelligent members of such societies usually do everything they can to escape such oppression, thereby either destroying that society or leaving it with a rump of the less intelligent and less ambitious which over time will degrade the genetic stock.
Nevertheless, in a free society everyone - conservative or liberal - is free to choose with whom they procreate. The long term survival of any racial characteristic within the human population depends in part upon the personal choices people make; if the racial characteristic of whiteness does not matter enough to people it will disappear over time now that the racial populations evolved over millennia have come back together. There is no right or wrong in this since “nature” does not care. However, given humanity is able to exercise free choice, conservatives could preserve the racial characteristic of whiteness if enough of them want to.
All racial groups are destined to reduce as a percentage of the overall population because racial heritage can only be preserved if one hundred percent of people in any ancestral line procreate within their racial group, which isn’t going to happen. However, as the numbers of each distinct racial group (i.e. white Negro and Asian) declines, my guess is that the concern for its survival will increase just as we care about tigers and polar bears more when they face extinction than when they were plentiful.
So my guess is that in the very long term, hundreds of years, there will be relatively few people around who have a pure white ancestry. However, since their forebears will have been more likely to have been conservative in the matter of racial mixing, hence that individual’s existence, the whites that remain will be likely to be conservative themselves. This, together with the fact that people value their ancestry more when they feel themselves to be in a minority, will probably ensure the survival of a relatively small population of whites. Of course this also applies to the other racial groups but for historical reasons these groups are likely to survive in greater numbers for longer.
Preservation, when arising from non-segregated personal choice, as opposed to segregation, should not result in genetic degradation.
Is it desirable to preserve ones racial group, does it matter if any of the races survive? The answer is it matters to some and not others; it is really just a matter of your values and preferences. In a free and liberal society in which peoples personal choices are their own affair as long as they do not restrict the choices and freedom of others, preservation of the kind I am talking of is, in my opinion, no ones business but the people making those choices.
For my part, I would like to see the continued existence of all races. In the very long term, when the vast majority of the world’s population is of mixed race and any single racially identifiable group cannot be perceived as a threat, I think such racial heritage will be seen as of value and people will strive to ensure it persists just as people try to ensure the continued existence of indigenous Indians in South America. Romans did not value artefacts in their daily life as we value those artefacts; it is a fact of life that something is only ever seen as worth preserving when it has almost gone. I’m prepared to bet that it is not just whites, Negroes or Asians of the future that value their genetic heritage but everyone, unfortunately I don’t think I’ll be around to collect my winnings.