Hillary. Bernie. O’Malley? Biden!

Right now, the Democratic field feels both random and predictable: we have Hillary Clinton, who should be the anointed one; Bernie Sanders, whose numbers defy reason; and Joe Biden, who everyone laughs at but no one counts out. Martin O’Malley, Jim Webb, and a few others round out the top tier, but don’t get near the attention that Clinton or Sanders are able to pull.

If Hillary or Bernie get the nod, then, who steps into the VP slot? That person could come from the current field—or he could come from inside agency land, with a little help from his twin brother.

Julian Castro and his identical twin brother Joaquin have been the objects of the left’s affection since Julian stole the show at the last Democratic Convention, and now they’re making their way toward the front lines of the progressives’ full court press against the GOP’s high-profile presidential bench.

In 2014, President Obama appointed former San Antonio Mayor Julian Castro to the post of Secretary of Housing and Urban Development. The appointment was less of a policy move and more of a tucking-away for safekeeping; Julian is being groomed, and many Democratic operatives believe he belongs in the #2 slot on the ticket:

Democratic National Committee Finance Chairman Henry Muñoz told BuzzFeed in May that Castro “deserves to be on the short list,” and New York City Council Speaker Melissa Mark-Viverito, who was born in Puerto Rico, said the concerted effort from Hispanic leaders to promote Castro reminded her of the united rally around Sonia Sotomayor when she was under consideration for a Supreme Court nod.

Clinton and Castro haven’t spoken since they appeared together on a panel in Washington in April, but people close to the campaign acknowledged that it’s politically useful for the candidate to keep his name in the public conversation, long before her operation formally starts vetting prospects. That way she can implicitly emphasize to Hispanic voters that she is taking their concerns about representation seriously.

“A lot of Latino Democrats are concerned about what happens if Marco Rubio becomes the [Republican nominee], or Jeb Bush, or even if Scott Walker becomes the nominee and he chooses Rubio to be the VP,” said a Democratic strategist close to the Clinton camp, adding that many see Castro as an easy solution to the dilemma.

And while the early pro-Castro campaign is risky, it effectively ensures he will be considered seriously when it comes time for Clinton to choose a running mate, assuming she wins the nomination.

Any high-profile run at the Vice Presidency (Castro as well as his allies deny the allegation) is bound to attract detractors—and Castro’s has—but the Clinton campaign’s focus on Latino outreach makes the position a logical target, and Castro is quietly making the most of it.

Julian Castro is just one of a set. His brother, Joaquin, rose in the Texas House of Representatives before securing a San Antonio-area Congressional seat. Joaquin Castro lives to antagonize Republicans—and (based on my experience) manages to do so while still maintaining an aura of likeableness and approachability that could prove tricky for conservatives aiming to counter his message.

Hillary Clinton, to her credit, has decided to harness Joaquin’s talents by making him part of her surrogate pool. He spent the end of last month campaigning for Clinton in Iowa, reaching out to the Latino community, hitting Bernie Sanders over lackluster outreach, and whipping up the base with horror stories about what a Republican-controlled Washington would look like.

From the Texas Tribune:

“I would submit to you that would be the largest and biggest and most brutal American dragnet this country has ever seen, and it would be scary and it represents the worst of America and it’s not befitting of those who seek the presidency,” Castro warned. “We’ve got to make sure these people are not elected to any office, much less the highest office.”

“If this is how they’re talking before the election, can you imagine what happens if one of those guys is sitting in the Oval Office, issuing executive orders?” he later said. “All of the advances that we’ve made, all the progress we’ve made towards comprehensive immigration reform — if these guys are elected, they are gone. It’s done.”

It was one of several themes Castro sounded Sunday as he worked his way across eastern Iowa into Des Moines, drawing low-key but appreciative crowds in his debut trip as a Clinton surrogate. It likely won’t be his last, as he — and possibly his twin brother, U.S. Housing and Urban Development Secretary Julián Castro — is expected to factor prominently in the Clinton campaign’s outreach to Latino voters.

Be afraid, little progressives—the GOP is coming to get you! It would be just another sales pitch if it wasn’t so effective, especially when it comes to topics like immigration reform.

Conservatives need to pay attention to this little dream team, because that’s exactly what the Castro brothers are—a team. They work well together, play off one another, and serve as a double megaphone for the most radical policies the far left has to offer. A ticket featuring one Castro brother, and backed by another, could prove a formidable foe for even a united GOP.

Follow Amy on Twitter @ThatAmyMiller