To some, the answer is simple: Our nations must be 100% White; all nonwhites must be avoided now and excluded later. Others, including myself, think that White Nationalism need not be entirely exclusive.
This discussion is framed in reference to the United States, a nation created by a blend of White ethnics who were 90% of its population up to 1960, but are now barely a majority.
Aims for a WN state. How exclusive our White Nationalist state need be depends somewhat on one's aim, one's conception of this state. The aim may be simply to preserve the whole of our people as they presently exist. As a WN with eugenic inclinations, my aim is to protect and improve the noble traits that distinguish Whites at our best from nonwhites, such as ingenuity, discipline, honor, honesty, trust and compassion. This aim allows for inclusion of exceptionally virtuous nonwhites, however rare and difficult to identify. Inclusion of a few nonwhites also adds genetic material to our gene pool that selective forces can act upon to our benefit, as likely occurred with Neanderthal genes. We could aim only for a nation that is generally White in character, but has an uninfluencial minority of carefully managed nonwhites.
WN must be racial. Based on an aim for White qualities as opposed to 'total Whiteness', one might suppose that a WN state need not be explicitly racial at all, that standards for inclusion could be nonracial. Not so. For one thing, our race is an extended family and we aren't going to boot out family members who have some shortcomings. Moral character, more important than intelligence, can scarcely be tested for; a studious examination of a person's life yields but an estimate. If such a test were possible, nonwhites who passed would likely have family members and offspring down the road with more race-typical traits. Practically, Whites must at least be favored by inclusion laws of a White Nationalist state.
Any nonwhites will increase. Limiting the growth and intermixture of a nonwhite minority would be problematic. Nonwhites have higher birthrates; they and their mixed offspring would increase their original portions. We've seen comprehensive measures to prevent integration fail, such as slavery and segregation in the United States and Apartheid in South Africa. Two races living in close proximity will amalgamate completely in the long run; we must assume this would happen with any nonwhite minority in our state. We must also be concerned about a 'slippery slope': given any portion of nonwhites allowed, liberals will urge more.
Our ideal may not be practicable. My ideal White Nationalist state has very few nonwhites, especially the darker sorts, i.e. <3%. However, we must also deal with reality: the practical challenge of bringing a WN state into being, faced with the urgent threat of extinction, faced with large numbers of nonwhites living among us, and faced with an enemy that demonizes us through their mass media. I think we are obliged to aim for something less than the ideal on account of these obstacles.
Nonwhite power must be reckoned with. In order to obtain our aims, we must have social and economic success, and we must operate in mixed areas where Whites are more receptive to our message. The reality - notwithstanding the "racism" propaganda - is that the nonwhites who live among us have a lot of power: physical, economic and social, as well as legal. If we have an icy cold or hostile attitude toward every one of them, various problems can result, such as losing business/employment, getting in legal trouble, becoming a pariah in one's neighborhood or social group, or getting assaulted. Being cold to random people is hard to justify (and for some of us, hard to stomach), and appears to confirm the charge that our views are based merely on irrational hate. With such a reputation our message may be rejected forthwith. Conversely, positive relations with certain nonwhites can facilitate the economic and social success we require, as well as rebut anti-WN propaganda.
Nonwhite support for the Cause? Getting help from nonwhites to promote White Nationalism seems absurd on its face. We all know - notwithstanding the "racism" propaganda - that nonwhites are better off within a predominantly White, multiracial state than without. And accepting nonwhite help implies having a close relationship, which is contrary to the aim of separation. Yet, I think that declining any support from nonwhites is poor tactics. For one thing, there are a few racial nationalists of other races whose aims are consistent with ours. There are also nonwhites who support important, controversial tenets of White Nationalism, such as the biological realities of race, the hostility of nonwhites, the corruption and subversion of Jews, the treachery and oppression of White elites, the foolishness and hypocrisy of liberals, or just the need for border control. Some of these sympathetic nonwhites have considerable media influence. Their support could be as limited as a citation in an internet post. But I think there are some nonwhites who (would) genuinely support us, especially if they could be included in our WN state.
Accepting nonwhite allies? I think that being open to accept nonwhite allies, who could ultimately join our nation, is a good policy. We can pledge to support those who support us - nonwhites who give real assistance to White Nationalism in our hour of need, instead of declaring to exclude every one of them regardless. I doubt that such allies would be numerous. But the offer rebuts the 'irrational hate' charge and gives us an avenue to be friendly with some nonwhites without contradicting our professed aim. It enables us to say that no nonwhite is necessarily our adversary. It also bypasses the problem of mixed Whites: people with some nonwhite ancestry who identify as White and take our side.
Segregation is essential. However, we shouldn't use an 'exceptions clause' as an excuse to freely integrate with nonwhites. Our aim is basically to separate from them, our raison d'être being that nonwhites' character is irreconcilable with our values and culture. The closer relationships we have with nonwhites in general, the harder separation will ultimately be and the more 'extreme' and hypocritical our aim will appear. This problem can't be erased just by pointing out that hypothetically you wouldn't have nonwhite friends if you lived in your dreamed-of WN state. You could explain that your nonwhite friends are only the rare exceptions, though not everyone will hear and believe this caveat. We need to minimize our relationships with nonwhites as far as possible, to segregate in pursuit of our separate, White Nationalist state.
Closing the deal. Once our fulfillment approaches, there will be no need for further compromise, nor any nonwhite immigration. Included nonwhites would be 'grandfathered in' on account of their loyalty and service. The highest standards would be required of any additional suitors, however cordial.