Incoming Democrats with significant national security experience plan to challenge President Trump over orders he has issued while in office, starting with his decision to deploy thousands of military troops to the U.S.-Mexico border to fend off a caravan of migrants seeking refuge in the United States.

At least nine Democrats newly elected to the House have served in the armed forces, intelligence services or in roles in the State and Defense departments — credentials, several officials said, that will give the party greater authority to scrutinize Trump’s use of the military for what they consider partisan aims.

Shortly before the midterms, Trump announced plans to send up to 15,000 troops to the southern border as a show of force against caravans of Central American migrants traveling north to the United States. House Democrats, who will have a majority come January, plan to investigate whether the order wasted resources.

According to several current and future members of Congress, the incoming veterans are expected to play an important role in advancing that probe. Other investigations are expected to focus on military affairs.

“You just have so many more Democrats now who have credibility on national security issues,” said Rep. Seth Moulton (D-Mass.), a Marine Corps veteran who spent the past year urging others with military backgrounds to seek office. “Now we have these amazing veterans who can take on these issues.”

For some, the issue is respect for the troops. In their estimation, Trump has failed on that front, despite his professed reverence for the military.

“He likes to pound his chest and talk tough, but he has not served our nation in uniform,” Rep.-elect Jason Crow (D-Colo.) said in an interview, noting that many service members sent to the border have already logged multiple combat deployments.

“ . . . They’re going to be spending yet another holiday away from their families in tents without running water,” he said.

Others questioned the logic of using an already overextended military to meet civilian migrants, most of whom are fleeing countries plagued by violence and poverty. A congressionally mandated study determined the military power of rival nations, including China and Russia, could soon eclipse that of the United States unless more strategic investments are made.

“We’re burdening them over and over again, and I want to know why this is the right thing to do,” said Rep.-elect Andy Kim (D-N.J.), who served in the Defense Department and the National Security Agency under President Barack Obama. Kim said Congress should determine whether Trump announced the deployment as a political ploy.

“I don’t want to see an ounce of politics when it comes to our troops,” Kim said.

Taking stock of Trump’s policies, incoming lawmakers also cited the war in Syria, the mission in Afghanistan and the perennial debate over a new authorization for military force as other areas they would like to investigate.

Rep. Adam Smith (D-Wash.), who is expected to take over as chairman of the House Armed Services Committee, has suggested that Democrats would challenge Trump’s plans to augment spending on nuclear weapons and establish a Space Force, and scrutinize his attempt to ban transgender people from serving in the military.

However, it is the president’s response to the caravan that has emerged as a lightning rod for critics of both Trump’s military and social policies — and the more Trump attempts to justify it, the more resolve Democrats appear to show in challenging it.

On Wednesday, Defense Secretary Jim Mattis and Homeland Security Secretary Kirstjen Nielsen visited troops stationed along the U.S.-Mexico border, delivering a message of thanks and encouraging them to ignore criticism of their mission.

Some Democrats surmise Trump’s national security leaders are making such demonstrations under duress.

“Our senior military leaders are forced to choose between what I know their inclination is — to stay out of this ridiculous mess — and their duty to obey the commander in chief,” said Rep.-elect Tom Malinowski (D-N.J.), a former assistant secretary of state.

Troops deployed along the border are expected to remain there through mid-December, though it is possible their deployment will be extended. Analysts estimate the operation will cost upward of $200 million through the end of the year.

Sitting Democrats have asked the Defense Department for a detailed briefing, though so far none has been scheduled.