Former counterterrorism official Matt Castelli on Wednesday is set to launch his bid for the 21st Congressional District in New York's North Country region, joining a growing field of Democratic candidates who are vying to unseat Republican Rep. Elise Stefanik. 

Castelli, in an announcement video obtained by Spectrum News 1, pointed to his service in Afghanistan and Iraq combatting terrorism and how he was inspired to joined the Central Intelligence Agency after the Sept. 11 attacks while he as a student at Siena College. 

"Later, I served in both President Obama and Trump's White Houses, but the January 6 attack against the Capitol, and our democracy, marked another watershed moment for each of us to step up and serve — just like 9/11," Castelli said. "It hasn't been lost on me that Congresswoman Elise Stefanik and I took the same oath to support and defend the Constitution against all enemies foreign and domestic. But it's clear to me, and countless other Americans that she violated that oath that day and in the weeks and months that followed."

Castelli plans to travel across the sprawling district to meet with voters "and talk about how we together can create a better vision for the future." 

Stefanik spokesman Alex deGrasse bristled at the comparison of the Jan. 6 Capitol riot in which supporters of former President Donald Trump stormed the building as the election of President Joe Biden was being certified to the Sept. 11 terror attacks, calling it "fundamentally not serious and deeply out of touch with North Country values."

"Congresswoman Stefanik will continue serving as a leading voice at the highest levels for North Country families with a sterling record of delivering results for military families, veterans and strengthening our national security. It is why she earned the highest number of votes ever for any North Country congressional candidate," deGrasse said. "There is plenty of time for politics in the months ahead for the grueling and crowded Democrat primary in New York’s 21st District, the week of the 20th anniversary of 9/11 is not that time.”

Castelli joins candidates Bridie Farrell, an advocate and former member of the U.S. national speedskating team, as well as attorney Matthew Putorti, in the race for the nomination in what is expected to be a closely watched House race. 

Stefanik has emerged as a national figure amid her support for Trump, and later ascended to a top leadership position as the House GOP chairwoman, unseat Trump critic Rep. Liz Cheney in the process. 

Cheney broke with her party amid the second impeachment of Trump in the wake of the Jan. 6 attack at the Capitol.