The House Freedom Caucus says that its mission is to "give a voice to countless Americans who feel that Washington does not represent them."

Yet in a surprising development, Florida Republican Rep. Anna Paulina Luna became the group's first member to quit when she announced her resignation this week. 

Luna complains that respect "was shattered last week"

According to Fox News, Luna explained her decision to depart via a letter which she sent to the House Freedom Caucus on Monday.

"I have consistently supported each of you, even in moments of disagreement, honoring the mutual respect that has guided our caucus. That respect, however, was shattered last week," she wrote.

At issue is Luna's attempted use of a "discharge petition." The procedure allows a lawmaker to force a bill to the House floor over objections from leadership provided that a requisite number of signatures are obtained.

The Florida representative is seeking a rule change which would permit new mothers and fathers to vote on legislation by proxy.

Congresswoman leaves caucus "with a heavy heart"

"Acting within the House conference rules – rules we all agreed to – I sought to bring a vote to the floor on a measure that would allow new mothers in Congress (fewer than 14 in our nation's history) and fathers, if they choose, to vote by proxy," Luna continued.

"This was a modest, family-centered proposal. Yet, a small group among us threatened the Speaker, vowing to halt floor proceedings indefinitely – regardless of the legislation at stake, including President Trump's agenda – unless he altered the rules to block my discharge petition."

Fox News noted how Luna made a point of praising House Freedom Caucus Chairman Andy Harris for conducting himself in a "gentlemanly" fashion.

Still, the Florida congresswoman indicated that she would nevertheless be departing from the House Freedom Caucus "with a heavy heart."

"I cannot remain part of a caucus where a select few operate outside its guidelines, misuse its name, broker backroom deals that undermine its core values and where the lines of compromise and transaction are blurred, disparage me to the press, and encourage misrepresentation of me to the American people," Luna wrote.

House speaker defends opposition to Luna's plan

Meanwhile, Fox News reported that House Speaker Mike Johnson defended opponents of Luna's proposal, arguing that it is "unconstitutional."

"A couple of our, a handful of our colleagues, have gotten behind the effort, and, look, I'm a father. I'm pro-family," the Louisiana Republican insisted.

"Here's the problem. If you create a proxy vote opportunity just for young parents, mothers and, the fathers in those situations, then where is the limiting principle?" Johnson asked.