[2/9/17]  The nation’s top Homeland Security official portrayed himself Tuesday as a steward of President Trump’s vision for border security as he laid out a path to fruition for some of Trump’s most bombastic campaign promises.

In his first appearance on Capitol Hill, Homeland Security Secretary John F. Kelly described plans for safeguards along the border that were more piecemeal than the “big, beautiful wall” Trump has touted.

Kelly said his agency would first build sections of wall and fencing where border agents see an immediate need and fill in gaps with ground sensors, surveillance blimps and other technologies that help detect illegal border crossings, emphasizing that the government lives in “a world of finite time [and] resources.”

“We’re not going to be able to build a wall everywhere all at once,” Kelly told the House Homeland Security Committee, adding that Border Patrol agents told him they preferred barriers they could see through rather than a solid wall.

But Kelly also said measures for the “extreme vetting” of travelers were under consideration that go further than visa officers ever have. The Homeland Security Department may demand that some visa applicants trying to enter legally hand over passwords to their social media accounts before flying to the U.S.

“They don’t want to cooperate, they don’t come in,” Kelly said.

In three hours of testimony, Kelly filled in specifics on several national security goals Trump has broadly set. And like a soldier carrying out orders, Kelly, a retired Marine general, shouldered the blame for the haphazard rollout of the president’s order temporarily blocking entry for refugees and all travelers from seven predominantly Muslim countries, even though he was largely left out of crafting the decree.

“The thinking was to get it out quick so that potentially people that might be coming here to harm us would not take advantage of some period of time that they could jump on an airplane,” Kelly said.

In retrospect, he said, “I should have delayed it just a bit” to prepare lawmakers and the public for the changes that were coming.

The confusion surrounding its implementation is “all on me,” Kelly said, putting himself in the awkward position of apologizing for the execution of a directive he didn’t see until the week it was issued and wasn’t told was coming until the day before it was signed.