Our sister blog has a piece breaking down the growing public rift between U.S. Sen. Johnny Isakson and two senior Republicans over what has typically been a broadly bipartisan topic – accountability at the Department of Veterans Affairs.

The Republican-on-Republican spat comes as Isakson, the chairman of the Senate VA Committee, nears the tail end of negotiations with senior Democrats on a large package of bills that would make it easier to fire VA employees not doing their jobs, among other changes. (Isakson said he's been working with the input of VA Secretary Robert McDonald.)

But in the process he’s angered his House counterpart Jeff Miller, R-Fla., the chairman of the House VA Committee, and former Republican presidential candidate Marco Rubio. The pair sent a letter accusing Isakson of halting negotiations on the proposal.

Here's more from our colleague Brad Schrade:

"We hope you realize that any piece of comprehensive veterans' legislation that doesn't provide the VA Secretary swift and comprehensive disciplinary authority for all VA employees misses the true mark on what ails the Department," the letter says.

The Rubio/Miller letter, which was posted on the House veterans affairs committee website, is notable because of the public strife within Republican ranks over what tack to take with the VA following the scandal that rocked the agency two years ago over long wait times at VA health centers.

Isakson's office didn't directly address the allegations in the letter, but his spokeswoman Amanda Maddox said his office hasn't backed away from the accountability problems. He supported Rubio's accountability bill when it came and passed out of his committee last July. A similar proposal was adopted by the full House last year, too.

The spat, which has spilled into public view in recent weeks, is a rare one given its very public nature and the fact that it involves senior committee chairmen from the same party. The House has passed several standalone VA accountability measures of its own.

House Republicans have taken to social media to pressure Isakson on the issue:

Schrade reports that Isakson expects his legislation will be unveiled within the next week or two. If passed, the package would be among the most substantial bipartisan compromises of Isakson’s Senate career, notable given this year’s highly-charged election-year atmosphere.