Ronald Reagan called it the 11th Commandment: "Thou shalt not speak ill of any fellow Republican."
For Democrats, though, it's always been a different story.
The latest evidence was offered Wednesday in the verbal assault that Colonie Democratic Assemblyman Bob Reilly launched against one of the nation's top elected Democrats -- U.S. Senate Majority Leader Harry Reid -- regarding Reid's desire to bring mixed martial arts to new york State.
"I'm appalled by the fact that the head of our United States Senate would make such statements," Reilly said of Reid.
"He's coming into New York and he's saying (MMA) is a good street fight, not even knowing that the advocates don't want to call it a street fight," Reilly said, referring to martial arts supporters' insistence that it's a legitimate sport with its own set of rules and values.
Reilly was responding to remarks that Reid, who represents Nevada, made last month regarding New York's ongoing ban on mixed martial arts contests.
"I'm going to see what I can do to help in New York," Reid told the Associated Press. "I'm aware of the issue, and I know a few people in New York. I'm going to see if I can talk a little sense to them."
"These (bouts), to me, are a fair street fight, and I've been around a few of those in my day," Reid said of mixed martial arts contests, in which competitors combine elements of boxing, kick-boxing, judo, wrestling and other martial arts.
One of the sport's major franchises, Ultimate Fighting Championship, is based in Las Vegas, where the promotion's owners, casino-developers Frank and Lorenzo Fertitta live.
They, along with UFC President Dana White, helped turn UFC into a national entertainment phenomenon.
From that standpoint, Reid's remarks could be viewed as a straightforward case of trying to help a local firm expand. But to mixed martial arts opponents like Reilly, it's a case of national politicians inserting themselves into what has been an ongoing local battle.
Supporters of mixed martial arts have for several years been trying to overturn the Pataki-era ban on the sport. Promoters say it would bring badly needed revenue the state's numerous sports and entertainment venues. New York is one of six states to ban the sport.
Reilly has long led a crusade against MMA, contending it's too dangerous, glorifies savagery and promotes violence among youths.
This year, the Senate approved a mixed martial arts bill that also had the support of Gov. David Paterson. But it remained stuck in committee in the Assembly, suggesting that Democratic Majority Speaker Sheldon Silver has ascertained there is enough opposition there to keep it bottled up.
Reid's remarks aren't the first time a national political figure has made a foray into New York politics.
Almost a year ago, it was revealed that the Obama White House had through an intermediary urged Paterson to withdraw from the gubernatorial race for fear that his weak showing in the polls would encourage Republican Rudy Giuliani to enter the fray. Paterson was subsequently embroiled in a series of scandals that led him to drop his run.
The extent to which the President influenced that decision is unclear, but observers say it's not unusual for federal lawmakers to weigh in on local or state issues. How it plays out depends on the individual circumstances in each case.
"It's idiosyncratic," Doug Muzzio, a political scientist at Baruch College, said of such interplay.
MMA promoters said they saw nothing untoward about Reid's trying to bring the sport to New York.
"As an ex-boxer and a fan of mixed martial arts, the Majority Leader is voicing his support for regulation of mixed martial arts in New York," said Ryan Toohey, a UFC spokesman.
Ultimately, Muzzio, added, getting MMA in New York would mean gaining the approval of Silver in the Assembly.
"The bottom line is, you've got to talk to Shelly," he said.
That might already be happening via New York's senior Sen. Chuck Schumer. His office late Wednesday couldn't be reached for confirmation, but one Capitol insider said he believed Reid has already talked to Schumer, in hopes of getting the senator to convince Silver to support the plan.
The trouble: There's enough opposition in the Assembly, especially among some of the women and older members, to keep mixed martial arts at bay for now, according to a source who is close to the issue but didn't want to be named.
"He's not going to roll his members over something like that," the person said of Silver.
The MMA dustup may also have created some headaches for Reid at home, prompting GOP opponents in the Silver State to say he's trying to help New York at the expense of Las Vegas. Reid is trying to overcome a challenge from Tea Party-backed opponent Sharron Angle.
"Why is Harry Reid trying to fill hotel rooms and restaurants in the Big Apple rather than Sin City?" asked Nevada Republican operative Chuck Muth in a recent blog posting.