As the political war over the crisis at the border escalates, Senate Democrats recognize that they need to do better in pushing back against Republicans in the big argument over the larger meaning of searing visuals of unaccompanied minors crossing into South Texas. They are aware they need to sharpen their case that in reality, the border is more secure than it has been in years.

In coming days, they will sharpen their use of metrics illustrating that in recent years there have been huge investments in border security, and amplify the case that the debacle is less a “border” crisis than a “refugee crisis.”

Senator Martin Heinrich of New Mexico has been tasked by Senate Dem leaders to take the lead in this big argument, and he conceded in an interview with me that Dems need to firm up their case. He laid out an argument that you’ll be hearing more of: If Congress doesn’t provide the funding Obama has requested to address the crisis, it could make the border less secure.

In the interview, Heinrich said Senate Dems would oppose Senator Ted Cruz’s insistence that we end deferred deportation for DREAMers as part of any short term response to the current crisis, flatly pronouncing the idea an “absolute nonstarter.”

“We are not going to allow Ted Cruz to use this as an opportunity to punish DREAM kids,” Heinrich told me. He dismissed Republican arguments that Deferred Action for Childhood Arrivals is a cause of the crisis: “The numbers don’t bear this out. We were seeing this surge out of Central America since before DACA was a policy. If DACA were [the cause] we’d see the same increase in Mexican immigration that we’ve seen from Central America.”

A Cruz spokesman backed down a bit today, clarifying he is not pushing for the deportation of those who have already received protection under DACA, but rather wanted border legislation to preclude DACA from expanding to more people, which would include other DREAMers. But Senator John Cornyn today generally supported Cruz’s idea for anti-DACA language in the GOP border bill. This will deepen the split between parties over the crisis, since Dems flatly oppose anything like it.

The battle over DACA is good political turf for Democrats, but Heinrich conceded that Dems were not yet making a strong enough case against Republican suggestions of a border in chaos. “That’s one of my frustrations,” he told me. “We need to get the facts on the table.” Heinrich said the case that the border is secure can be made with several clear DHS data bullet points sent over by his office:

1) In FY 2012, the Federal government spent $17.9 billion on immigration enforcement. That is $3.5 billion more than the budgets of all other Federal law enforcement agencies (FBI, DEA, ATF, Secret Service, and U.S. Marshalls Service) combined.

2) Since 2004, the number of agents along our borders has increased by 94 percent to over 21,000 Border Patrol Agents today.

3) Since President Obama was elected, immigration crimes have become the most prosecuted crimes in Federal court.

4) From FY 2009-2012, DHS has seized 71 percent more currency, 39 percent more drugs, and 189 percent more weapons along the Southwest border as compared to the last four years of the previous Administration.

Meanwhile, according to DHS statistics, removals from the border region have actually gone up; it’s removals from the interior that have gone down, reflecting Obama’s shift in priorities to the border and away from deporting low level offenders with lives here. Meanwhile, a Pew study last September found the population of undocumented immigrants here has remained relatively steady in recent years, after going up from 1990-2005.

“All of the trends and data have been quite positive in recent years,” Heinrich said. “We have way more border patrol agents. We have dramatically more mobile surveillance systems. We’ve reduced illegal crossings. All this makes it clear this is not a border-driven crisis; it is a refugee crisis that has shown up at the border.”

Many kids are simply turning themselves over to law enforcement, which suggests this isn’t a security problem and is instead being caused by factors such as Central American violence and awareness of holes in our legal system. What’s more, according to an Arizona Republic investigation, the vast majority of child crossings are happening only at the Rio Grande sector — undercutting GOP suggestions of border chaos everywhere. Indeed, Dems will increasingly argue that funding to address this crisis in one sector must pass, lest border security elsewhere be compromised as Border Patrol agents are required to deal with kids rather than securing the border.

“If we don’t pass this supplemental, we’re going to see this little stretch of the Rio Grande pull resources from elsewhere and undermine years of progress in effectively securing the border,” Heinrich said. “Obstruction from Republicans is a serious threat to our border security. We need these resources to deal with the refugee crisis.”

Now, it’s true that suggestions of a “refugee crisis” could conflict a bit with the White House, which is open to changes to the 2008 trafficking law that would expedite removals, which many Senate Dems oppose. And it’s unclear how those differences will be resolved. But whether you call this a “refugee crisis” or not, you will hear Dems united in increasingly making the case that the crisis just isn’t a border security problem.

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.