"Open borders" is a phrase usually heard in the context of international borders only.

We hear far less about the issue of open borders between member states within a confederation or union of states.

After all, no one thinks twice of crossing the borders between member states within the United States of America. Increasingly, one is similarly unimpressed when crossing from one EU member state to another in Europe.

Often unnoticed is the way that disappearing patrolled orders between states have helped pave the way for advocates of ever greater consolidation of power in the hands of the central government.

It's a process that has taken decades—or even centuries in some cases—but it is real.

This process of centralization often proceeds in four steps:

One: So long as there are internal borders unregulated by a central government, each member state can control — or not control — the flow of migrants, goods, and services locally. Thus, if one state has legalized a dangerous substance or device, neighboring states have the legal prerogative to stop those substances and devices at the member state's border. The degree to which each state does this — if at all — will vary. There is no need for a universal policy, because each member state is responsible for regulating those persons or goods it claims must be controled. Only the residents within that specific state are subject to these rules, while outsiders are free to ignore them.

Two: But some activists and lawmakers recognize there are benefits to open borders. So, seeking greater ease in the movement of goods, capital, and workers—and in some cases seeking to transfer the cost of border enforcement to taxpayers outside its jurisdiction—member states lobby the central government to minimize or abolish state-level control of borders.

Three: But this does not come without risks and externalities. Without union-wide and uniform laws, pro-regulation activists insist that "bad actors" and prohibited goods can too-easily cross from less regulated areas to more regulated ones.

Four: So a solution is proposed: the central government will assume the cost of border control, transferring border control activities to the new union-wide border encompassing all member states. Within this border, lawmakers seek union-wide uniform policies. "Bad actors" are declared to be criminals in all jurisdictions and the "dangerous" substances and devices can now only legally enter by crossing international boundaries. The central government is now expected to provide enforcement to maintain this new status quo. What had once been the responsibility of the member states has been transferred to a newly empowered central government.

The problem is one of increasing threats to "self-determination." As Ludwig von Mises notes in Liberalism, political "self-determination" for individuals is often best secured through a decentralized political structure where local laws are created and controlled by the local population. By removing local control of borders, self-determination is lessened.

This process is now underway in Europe, where the EU government is moving closer to demanding "harmonization" of tax rates and that all states within the open-border zone adopt more stringent gun control laws. But for now, we'll stick to examples in the United States:

Cross-Border Travel as an Excuse for National Gun Control

In the gun control debate, it has long been argued that the lack of patrolled borders between states means a greater need for uniform nationwide gun control. In an analysis from National Public Radio, for example, the author concludes that the high homicide rates in Washington, DC, and Chicago are partly to blame on gun laws in neighboring states. According to political scientist Philip Cook, the stringent gun laws in places like Chicago are "only at best partially effective, because the borders are permeable."

Were there not free movement from state to state, of course, it would be more difficult to argue that Wisconsin is to blame for Chicago's homicide rate.

The argument by gun control advocates in this case follows a now familiar pattern: the presence of a relatively low amount of regulation in one member state (i.e., Indiana) is viewed as a threat to surrounding member states, who then insist that open borders between states mean that low-regulation states must change their policies to match the high-regulation states.

The Federalization of Immigration

Up until the late nineteenth century, immigration control had been regarded as a state matter. States heavily impacted by immigration—especially New York and Massachusetts—had imposed a variety of laws restricting the movement of immigrant paupers and requiring that bonds be paid on new immigrants to ensure that they did not become a burden on public funds. As late as the 1870s, bills aimed at federalizing immigration policy were killed by majorities in Congress.

Part of the reason that there was a lack of a national consensus was that views of immigrants nationwide were hardly uniform. Some frontier states actively sought immigrants in order to increase the development of farmland and increase state populations. These ongoing regional differences are a reason President Cleveland in 1897 vetoed legislation further restricting immigration because many states and territories of the US—especially those bordering Canada, which provided migrant labor to American farmers—benefited from migrants. Cleveland noted that these parts of the country "have separate and especial interests which in many cases make an interchange of labor between their people and their alien neighbors most important."

Nevertheless, it was recognized that migrants could move freely from immigrant-friendly states to immigrant-unfriendly states. So, anti-immigrant forces had increasingly lobbied for greater federal controls on the external border. No long after, the US Supreme Court in 1876 ruled that it was necessary to provide "a system of laws in this matter applicable to all ports and all vessels" in order to settle a long-standing "matter of contest and complaint." By the twentieth century, the autonomy once granted to states on the immigration issue was all but forgotten.

Prohibition and the Drug War

Regulating guns and migrants haven't been the only excuses given for expanding federal power in the name of national uniformity. Centralized control was also deemed to be necessary in order to control the transport and manufacture of alcoholic beverages. In the years leading up to the adoption of nationwide prohibition, all but sixteen states had adopted their own versions of prohibition. For the moralists, however, this wasn't enough. Those states where alcohol remained legal—mostly states with large numbers of Catholics and ethnic Germans—offered a haven to residents of "dry" states, who could easily cross over into the "wet" states. Even worse, people could illegally import alcohol into dry states from wet ones with relative ease. By imposing nationwide prohibition on everyone, however, access to alcohol could be more easily attacked.

We see similar issues today as some states have begun to legalize recreational marijuana much to the dismay of officials in neighboring states. Once again, the answer is alleged to be the federalization of policy and the abolition of local prerogatives. In 2014, two marijuana prohibitionist states, Oklahoma and Nebraska, unsuccessfully sued Colorado in response to its legalization of recreational marijuana. The two states were concerned that the lack of a patrolled border between Colorado and its neighbors was an unacceptable threat to the public in prohibitionist states. Thus, the two states petitioned the court to declare state law null and void and to rule that federal law reigns supreme in matters of drug prohibition. Fortunately, on this particular issue the federal courts have not yet decided to declare federal law supreme, as they have many times before.

When Erasing Borders Isn't a Problem

Unfortunately, economic integration between member states in the US did not come organically or unilaterally. It was imposed from above, often with the goal that low-regulation states would not provide a haven from high-regulation states. We have seen this in political fights over alcohol, over migrants, and with guns.

Experience with these political fight now strongly suggests the lowering of borders do not pose a threat to self-determination and do not enhance the power of the central state only under the following conditions:

Border controls are decreased unilaterally by each member state in an ad hoc and decentralized manner. The central government is too weak (or lacks the legal authority) to impose uniform nationwide laws without widespread consensus. Member states bring to the table a significant amount of tolerance for their neighbors, and for the fact that people might do things differently in other places. In decades past, for instance, it was more often accepted that some places have stringent gun laws and other places don't. In the minds of many policymakers, this created certain risks and externalities, but these were tolerated in light of the ideological notion that not every aspect of daily life ought to be regulated from the center.

It is no longer clear, however, that we live in a political environment where this sort of tolerance or decentralization is still valued. It now appears that a lack of functioning borders between member states—instead of promoting unity and cooperation—may actually be promoting conflict and further centralization. For example, were there a meaningful border between California and the rest of the United States it is unlikely that the rest of the nation would regard foreign migration as the high-stakes political issue it now is. Similarly, if it were not so easy to travel unobstructed from gun-friendly Indiana to gun prohibitionist Chicago, we wouldn't be hearing about how we need federal action on gun control.

The result is something similar to what we see from political centralization in general. By ending legal and physical separations between culturally and legally diverse political jurisdictions, opposing sides end up fighting bitterly over who controls the central government. Ironically, the attempt at building unity through erasing borders has increased the stakes of who controls the central government and influences its policymakers. In the long term, this is likely to bring ever greater regional conflict.