It was something of a surprise when California Governor Jerry Brown announced last week that he would send a few hundred National Guard troops to the border in response to a Trump administration plan to back up US Customs and Border Protection agents with troops from around the country. However, from the outset Gov. Brown made clear he would not contribute to a human wall aimed at stopping illegal immigration. Here’s how the LA Times reported it last week:

Gov. Jerry Brown agreed Wednesday to take money but not marching orders from President Trump in deploying 400 National Guard troops to various locations around the state, insisting any service members near the border would not enforce federal immigration law.

“Your funding for new staffing will allow the Guard to do what it does best: support operations targeting transnational criminal gangs, human traffickers and illegal firearm and drug smugglers along the border, the coast and throughout the state,” Brown wrote in a letter to Homeland Security Secretary Kirstjen Nielsen and Defense Secretary James N. Mattis.

But it turns out that much of what the border patrol does is related to stopping illegal immigration. Therefore, it’s not very easy to find jobs for California’s Guard troops that aren’t, at least potentially, tainted by stopping illegal immigration. Today, the Associated Press reports California has rejected most of the jobs border patrol asked its troops to perform:

The state informed federal officials it will not allow its troops to fix and repair vehicles, operate remotely-controlled surveillance cameras to report suspicious activity to the Border Patrol, operate radios and provide “mission support,” which can include clerical work, buying gas and handling payroll, according to officials with knowledge of the talks who spoke condition of anonymity because they were not authorized to discuss the matter…

Evan Westrup, a spokesman for the governor, did not immediately answer detailed question about California’s rejection of specific guard duties.

Talks between U.S. and California officials about the duties the California troops would perform soured Friday and over the weekend after state authorities told federal officials that they would not participate in vehicle maintenance and the other jobs outlined for an initial phase across the border in California, Arizona, New Mexico and Texas, the U.S. officials said. The other border-state governors — all Republicans — have openly embraced Trump’s plans.

The state’s position infuriated some federal officials because the restrictions California officials wanted to impose on what the state’s troops would not do were considered onerous, the officials said.

As I’ve pointed out before, National Guard troops are not authorized to arrest anyone coming across the border so there’s no danger of them replacing actual border patrol agents when dealing with people coming across illegally. Mostly the Guard troops are being asked to take up support roles that free up more actual Border Patrol agents to be out on the front lines, so to speak.

I can understand why Gov. Brown would not want his Guard troops using surveillance cameras to notify border patrol agents of people sneaking across the border. Brown, like most elected Democrats these days, supports de facto open borders, so helping arrest illegal immigrants would probably create a backlash on his left flank. But why can’t the Guard troops do vehicle maintenance or office work? That doesn’t make a lot of sense. Is the idea here that those vehicles will be used to arrest border crossers and therefore California won’t participate in any way?

Here’s the fundamental problem with Gov. Brown’s approach. Border patrol agents don’t necessarily know by looking which people coming across the border illegally are people looking for jobs and which are criminals bringing in drugs, guns, or engaging in human trafficking. The only way to gain control over these latter problems is to gain control over the border itself. If Brown doesn’t want his troops involved in that larger effort, then he doesn’t really want to deal with the crime problems open borders invite.