On my way to work on Saturday, I ran into a protest march.

I was walking along and suddenly surrounded by signs about “kids in cages” and white women wearing white Planned Parenthood T-shirts imprinted with slogans about keeping families together.

Since we were in Southern California, it was the reaction of people passing in cars that served as a barometer of an issue’s popularity. There was a lot of honking, people yelling encouragement from car windows.

When the issue first exploded onto the news a couple weeks ago, I thought it was devastating for the administration, especially the images of kids lined up between military-style tent dormitories. The state taking away kids – that was an issue that the Christian wing of the Republican Party could not handle.

But, day after day, the news stories seemed repetitive, and the concept of “compassion fatigue” came to mind. My aunt who is upwards of 90 condemned the administration’s policy but, in our weekly phone calls, she added something like, “Isn’t there any other news?”

So I checked the Democratic Party’s Twitter feed @TheDemocrats after the demonstrations. I wrote in May that a get-out-the-vote video pinned at the top of the site was three months old.

It’s still there and now it’s almost five months old. It was followed by six videos and tweets about the family separation protest marches, followed by a tweet about LGBTQ pride month.

So the Democratic leadership made the calculation that the border was their big issue, as a subset of their locked-in theme of identity and civil rights.

I then checked Bernie Sanders’ Twitter site. His top tweet briefly gave support for the demonstrators with no imagery and moved on to long social security lines followed by promotion of a livestream town hall meeting between Sanders and low-paid workers for Amazon, Walmart, Disney and McDonald’s. He underplayed the border issue and stuck mainly with an economic theme.

He clearly did not make the same calculation as the Democratic machine. And it may be because he sensed a trap.

A couple weeks ago, I asked a Courthouse News employee and Trump supporter about the family separation issue and she demurred, saying she still had to find out more about it. In an aside, she correctly noted that immigration was Trump’s leading edge issue.

One of the lessons of war is that the side that picks its terrain can win, or at least greatly increase the odds in its favor. Politics is like that.

So is immigration the terrain that favors Democrats or Republicans? That is a slam dunk of an easy answer.

A politician here in California that I think has a lot of presence and potential is Eric Swalwell, a young, white congressman from the East Bay whose district is split roughly in thirds, white, Hispanic and Asian. His first tweet supported keeping families together in general terms, his second tweet was about a constituent who put him on the back foot by accusing him of being for open borders.

I then checked the GOP Twitter feed. The top tweet was one hour old as opposed to five months old. It was topped by a strong graphic with a slightly revolutionary tone, “DEFY HISTORY” in red letters against a dark gray outline of the capitol.

The site was dominated by an economic theme. The top tweet was about tax cuts, the second about farmers hurt by China, the third advertised 40 percent off for Republicans hats and other paraphernalia. Among the tweets was a link to The Hill’s poll last week showing Trump’s approval is at 47 percent with – this is what’s amazing – support among Hispanics growing by 10 percent.

Over my oatmeal on Saturday morning, I read a news analysis in The New York Times comparing the immigration crises in the EU and the U.S. I thought about one passage on my walk to work among the demonstrators. “Immigration, unauthorized or otherwise, is just one of the changes that bring about a feeling of the loss of control. Economic dislocation, changes in social hierarchies and demographic change can all produce the same effect.”

That list – economic dislocation, changes in social hierarchies, demographic change – that is at the core of Trump’s support. That’s why it won’t change. So when the Democratic leadership goes all out on immigration, it is wading into a tide of anger connected to economic well-being.

That used to be their issue. They lost it. And the Democrats have been losing elections at the state and federal level for ten years now, going down by almost 900 elected positions since 2008. Any party that follows that sorry history with a mega-loss to a reality TV star in a presidential race – that party would in any normal democracy kick out its leadership.

But that hasn’t happened. The same folks keep on banging the civil rights drum. While the GOP essentially steals their lunch, using social media effectively and focusing on economic issues, with a bit of revolutionary fervor.

The concern among those demonstrators I ran into, well intentioned as they are, should be that come the midterms, they won’t be flipping anything. Because their leadership is lost, wandering in the past.