US President Donald Trump tweeted on Sunday that he had scrapped meetings at Camp David between himself, Afghanistan President Ashraf Ghani, and Taliban envoys. "They were coming to the United States tonight," he tweeted.

After a Taliban suicide bomb claimed the lives of a US servicemember and 11 others, Trump called off the unannounced visit.

"First of all, we should state that this was a horrible idea to bring the Taliban to Camp David, especially in the days running up to September 11," Rep. Max Rose, a New York Democrat and Afghanistan veteran, said on MSNBC on Monday. Other veterans in Congress agreed; "As we head into the anniversary of 9/11, I do not ever want to see these terrorists step foot on United States soil. Period," GOP Rep. Michael Waltz of Florida, a former Green Beret, told CNN on Sunday.

"It is unusual for peace talks to be proposed in territory that is not neutral, save in those cases where one side has been utterly subjugated by the other," Adrian Bonenberger, an Afghanistan veteran, told Insider.

The future of the peace talks, which have endured for 10 months, is now in doubt.

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President Donald Trump tweeted on Saturday that he had scrapped secret meetings at Camp David between himself, Taliban leaders, and Afghanistan President Ashraf Ghani after the Taliban claimed a suicide bombing in Kabul that killed a US soldier. Some veterans who fought the Taliban in Afghanistan reacted to the news that Trump planned a secret meeting with shock and outrage, with one veteran calling it a "horrible idea."

"If there was an opportunity to declare peace (or meaningful progress toward peace) in good-faith on the anniversary of 9/11 or on any other day, I would celebrate with equal enthusiasm," Adrian Bonenberger, writer and a two-time Army veteran of the Afghanistan war, told Insider via email.

"Having said that, it is unusual for peace talks to be proposed in territory that is not neutral, save in those cases where one side has been utterly subjugated by the other. I do not believe that is yet the case with the Taliban, or the Afghan government, and is certainly not the case with America's proud and undefeated military."

Rep. Max Rose, a Democrat representing Staten Island, spoke about Trump's decision to invite Taliban representatives to the presidential retreat at Camp David on MSNBC's Morning Joe on Monday.

"First of all, we should state that this was a horrible idea to bring the Taliban to Camp David, especially in the days running up to September 11," Rose said. The summit was planned for Sunday, Sept. 8. Rose, an Afghanistan veteran, said he still hoped for a peace deal between the US and the Taliban, but that the US needs a response mechanism in the case that the Taliban harbors or assists international terrorists.

Republican Rep. Adam Kinzinger, an Air National Guard pilot who flew missions over Afghanistan, tweeted, "Never should leaders of a terrorist organization that hasn't renounced 9/11 and continues in evil be allowed in our great country. NEVER. Full stop," in response to the president's announcement.

"As we head into the anniversary of 9/11, I do not ever want to see these terrorists step foot on United States soil. Period," GOP Rep. Michael Waltz of Florida, a former Green Beret, told CNN on Sunday.

Camp Davis is an important location to Americans.

According to a report from The New York Times, it was Trump who thought to bring the Taliban to Camp David, where the historic Camp David Accords were negotiated, easing longstanding hostilities between Israel and Egypt.

Trump's National Security Council was left in the dark about the proposed meeting, which fell apart nearly as soon as it was planned, according to The New York Times. The Taliban hoped a trip to Washington would mark the end of negotiations, while Trump wanted to use the Camp David meetings to put the finising touches on a peace deal, or at least appear to have done so.

"There's going to be conflicted emotions from people who served in Afghanistan about these peace talks, or potential peace talks," Jeremy Butler, the executive director of the Iraq and Afghanistan Veterans' Association and aveteran of the Iraq war.

"Camp David is a place of high importance for the US," Butler said. "You could say that it shows the seriousness of these talks."

But, in keeping with that, Butler told Insider that the stalled peace talks "should be long-term, in-depth discussions that should not be rushed," and should not be done to fit a timetable — or coincide with an anniversary, like September 11.

Regardless of the outcome of the talks, Butler said, the important thing to keep in mind is that troops, whether US forces or those of allied countries, will likely be in Afghanistan for the foreseeable future, and negotiations should create the best possible outcomes for the US and its allies, as well as Afghans.