A common complaint made by some progressive thinkers is that justice activists are far too splintered and/or obsessed with a single progressive issue, such as ecology, human rights, or animal rights. The complaint is that “single issue activists” fail to see the common ground of opposing unjust or unsustainable exploitation among the various single causes and often blindly oppose each other instead of cooperating. This failure to understand the common denominator and corresponding failure to cooperate undermines the efforts of everyone seeking justice and sustainability. The answer is alliance politics, where we build bridges and connections among the various single issues, and become stronger collectively and individually as a result.My purpose in this essay will be to analyze the call for alliance politics and set forth what I see as its strengths and limitations. I will argue for a middle ground between what I see as two extremes. One extreme being that of pure single issue politics whereby one sees only the differences between the various issues (ecology, animal rights, human rights and egalitarianism, economic fairness and opportunity) and scoffs at or ignores one, some, or all other justice issues. The other extreme being that of pure alliance politics whereby one sees only the similarities among the various issues and fails to see important differences and why others might choose to focus exclusively, and even “obsessively”, on one issue.
The Common Ground: The Strength of and Reasons for Alliance Politics
The common ground of all progressive movements is their opposition to some form of unjust or unsustainable exploitation perpetuated by excessive self-interest, myopic views, and/or a general herd mentality. Whether the issue is speciesism, slavery, racism, sexism, heterosexism, or eco-destruction, there is always an exploiter or an oppressor, sometimes including the vast majority of society, who ignores the interests of a certain “other” in favor of some irrational prejudice (e.g. hate or intentional indifference) or self-serving benefit derived from the exploitive or oppressive behavior and attitude. This common ground is the substance underlying all justice movements.
Because of this common ground, anytime a “progressive” person or group espousing one such cause (e.g. ecology or gay rights) trivializes or intentionally ignores another cause (e.g. anti-speciesism or economic opportunity), that person or group undermines the underlying substance of his or her own cause by arbitrarily (and often unwittingly) endorsing exploitation or oppression which is merely in different form.
By recognizing the underlying substance – the injustice at the root of what progressive movements are opposed to – we can unite at least to the extent of recognizing each single issue’s “baseline” or “minimum standards” of behavior and attitudes. While attempts to maximize any given single issue’s goals may well intrude on another single issue’s baseline, I cannot think of one case where any single issue’s baseline intrudes on any other single issue’s baseline. Of course, one might object that it depends on how one defines a baseline, but using the most commonly promoted baselines as definitions, it’s unlikely that any of them would conflict.  In fact, not only is it unlikely that baselines would conflict, but most baselines are mutually beneficial. For example, veganism, which is the baseline for the animal rights movement, would do wonders for ecology if adopted by the vast majority of the world’s human population. In the next section of this essay, we’ll get into some of the conflicts that arise when we try to maximize the goals of any given single issue, but there can and should be general agreement and support among progressives in the commonly promoted baselines of single issues.
The Differences: The Limitations of Alliance Politics
While there is much common ground among the various movements fighting unjust or unsustainable exploitation and we can and certainly should respect other movements’ baselines by not violating those baselines, there are also important differences – both in the causes themselves and the people who dedicate themselves to a cause – that might motivate some of us to focus solely on one issue and avoid involvement in actively promoting another (while not violating the baselines of the other movements). 
Differences Between the Issues Themselves
For example, the ethical grounds of protecting the environment are significantly different from the morality of protecting the important interests of individual sentient beings. In the case of protecting the environment, our obligation is not directly to the environment (water, air, minerals, and species), but directly to current and future generations of individual sentient beings (human and nonhuman). Our obligations to protect local and global eco-systems are indirect duties. The nature of this indirect obligation is that it is not wrong to exploit the environment per se, or use it solely as a means to our ends, but to use it sustainably so that future generations of individual sentient beings can survive and thrive in the same environment years, decades, and centuries from now. If we fail to make significant changes in our use of the environment, there may be no environment in which our great grandchildren can possibly survive, much less thrive.
In contrast, our obligations toward sentient beings (including sentient nonhumans) are direct obligations to individual beings to not exploit or use them solely as a means to our ends, but to respect and treat them as ends in themselves. Our current use and treatment of animals is deplorable beyond the ability of language to articulate it. It is simply the worst atrocity humanity has ever engaged in as a species.
The contrast in the respective moral grounds of each justice movement and the differences in the problems they face make them specialized enough to call for specialized and highly-focused movements, organizations, and individuals to tackle them.
Differences Between Activists as Individuals
There are also differences in the personalities and life experiences of individual advocates of various issues that motivate one to fight a particular injustice. Having a strong personal experience of a particular event or situation can often be the catalyst for dedicating one’s life to a certain issue. Being an individual who has experienced injustice personally can motivate lifetime dedication to a movement. Having a previous expertise in a given area can also lead to involvement with a particular movement.
When we combine the differences in the various forms of oppression or exploitation with the differences in the individuals who choose to fight a particular injustice, it is no wonder that people will gravitate toward one or another movement.
Even within a given movement, one might be motivated to focus on a single issue within the movement due to expertise or life experiences. This is fine with the caveat that one does not ignore or refuse to acknowledge a vital root connected with the larger movement, as I discussed in the essay entitled, Picking the Low Hanging Fruit: What Is Wrong with Single Issue Campaigns?. For example, animal activists concerned about whales, seals, or fur cannot profitably ignore the fact that the underlying foundation of those abuses is the fact that so few people in our society are vegans (with the moral reasons implied in the term “vegan”).
Conflicts Between Movements: Maximizing the Interest of One Movement May Violate the Baseline of Another
There’s a difference between achieving an acceptable baseline and maximizing the interests of any given movement. A good example of this is when environmentalists attempt to maximize the health of an ecosystem by violating the individual rights of animals living in such an environment. The best way to maximize the health of any specific ecosystem is to free it from human interference. But too often, humans create a problem via interference, then seek to “cure” the problem we created by further interference. The “cure” often includes intentionally killing innocent inhabitants when there’s an alternative that avoids such intentional killing. Further, our “cure” often leads to more intractable problems in the pulled-string-that-never-ends. We don’t “cull” the human herd to maximize ecosystems (or even to meet acceptable ecological baselines), and we should not “cull” other species for the same reason: it’s a violation of an individual’s right to his or her life. Bad things happen in life, but we don’t need to add to it with the arrogance of “managing” nature.
We need to accept trade-offs when it comes to attempting to maximize the interest of a given movement. We need to be creative and look for alternatives rather than to simplistic solutions that override the rights of others. Dilemmas may arise, but we should not manufacture false dilemmas or ignore viable alternatives because we scoff at or fail to take seriously the baseline of another justice movement.
Conclusion: Respecting the Common Ground and Acknowledging the Differences
Respecting the common ground of the substance of exploitation or oppression per se to all justice issues is important. When we don’t respect that common ground in any given movement (e.g. animal rights), we invariably undermine the foundation of our own claims about fighting injustice elsewhere. Respecting the common ground necessarily means taking seriously and behaving in accordance with other movements’ baselines or minimum standards.
On the other hand, we don’t need to be an activist for every, or even any, given cause. As long as we’re blameless – which is to say as long as we’re not violating baselines or intentionally engaging in injustice or unnecessary harm ourselves – we should pick our causes and issues as we desire and enjoy involvement in them. And if activism isn’t our thing, but we’re not contributing to a movement’s problem in any significant way, that’s fine too.
On that note, go vegan.
 The “commonly promoted baselines” I’m referring to essentially means one is not participating, in any meaningful sense, in the harm or injustice that caused the single issue movement to arise in the first place. It is the mission of the single issue movement to eliminate such harm or injustice from society. Examples include: 1) Avoiding racism, sexism, and heterosexism by treating people of different ethnic, racial, sex, or sexual preference groups fairly and equally to our own; 2) Avoiding slavery (or forms of it) by avoiding sweatshop products (clothing, etc.); 3) Avoiding speciesism by being a vegan, leaving animals alone (except to help them in certain human-created situations) and not participating or contributing to the exploitation of animals; 4) Avoiding eco-destruction by living simply and taking steps to reduce our eco-footprints as much as reasonably possible, especially in the “big decisions”, such as how many offspring one produces or one’s choice of occupation.
 One might confuse or conflate what I’m saying here with what I said in the essay entitled “Picking the Low Hanging Fruit: What’s Wrong with Single Issue Campaigns?”. The difference is crucial. While unjust or unsustainable exploitation may be a common denominator among various otherwise diverse problems giving rise to various causes and movements, racism, sexism, eco-destruction, and animal rights are disparate enough problems to warrant highly specialized treatment by specialized movements, organizations, and individuals. Further, none of these single problems is the root, or completely overshadows, all of the others in importance by magnitude or nature whereby once we solve one of them, the others will follow virtually automatically.