The Senate Ethics Committee that will examine the actions of Sen. Bob Menendez, D-N.J., and Al Franken, D-Minn. — and possibly Roy Moore if the Republican wins his Senate race in Alabama next month — has rarely taken significant action to punish lawmakers, and has only moved to oust people if they are convicted of a serious crime or are a member of the Confederacy.

That history shows it's nearly impossible to get kicked out of the Senate, and that the panel isn't likely to punish Menendez, Franken, or Moore, according to some watchdog organizations.

“I would not expect any action to come out of the Senate Ethics Committee on any of these charges,” said Craig Holman, Government Affairs lobbyist for the consumer advocacy group Public Citizen. “The Senate Ethics committee is not only very slow, it is dysfunctional and fairly secretive. We really don’t know what is going on when it comes to ethics enforcement the Senate, except for the fact that very little is going on.”

Senate Majority Leader Mitch McConnell last week called on the Senate Ethics Committee to investigate Franken, D-Minn., over allegations of sexual misconduct against at least one woman who said Franken forced her to kiss him during a USO tour and later fondled her in a now-widely published photo that was taken when she was sleeping. Franken himself agreed to an Ethics Committee investigation, which other lawmakers agreed was the right response.

McConnell also called on the Ethics Committee to investigate corruption charges against Menendez, D-N.J., whose criminal trial in New Jersey ended in a hung jury earlier this month.

“Senator Menendez was indicted on numerous federal felonies,” McConnell said in a statement. “He is one of only twelve U.S. senators to have been indicted in our history. His trial shed light on serious accusations of violating the public’s trust as an elected official, as well as potential violations of the Senate’s Code of Conduct.”

McConnell has threatened an ethics probe of Roy Moore, the Republican Senate candidate from Alabama who faces the voters on Dec. 12. Moore has been accused of pursuing teenage girls and sexually abusing minors.

Related: Roy Moore's Senate future: Expulsion

But watchdog groups are skeptical in light of the panel's 53-year history. In the past decade, records show, the committee of three Republicans and three Democrats has issued a handful of letters admonishing individual senators, but has otherwise found no fault with Senate lawmakers in either party.

The last Senate expulsions occurred in 1861 and 1862 when 14 Democrats were ousted over “support for the confederate rebellion.”

Censure, the next most serious disciplinary action, last occurred in 1990, when Sen. David F. Durenberger, R-Minn., was “denounced” in a Senate floor vote for for misusing office funds and other violations.

But Senate lawmakers allowed Durenberger, the former Intelligence Committee Chair, to keep his seat. He served four more years in the Senate before retiring and then pleading guilty in 1995 to watered-down charges of abusing his congressional expense account.

At the time of his censure, lawmakers in both parties were forgiving, and provided Durenberger with hugs and handshakes after meting out his punishment as he sat in the chamber, the New York Times reported back then.

''After all this is over and we denounce him,'' Sen. William L. Armstrong, Republican of Colorado, said at the time, ''we still want him to be our friend.''

Any Senate disciplinary action can require years of preliminary investigations. Sen. Bob Packwood, R-Oregon, for example, was accused of grave sexual misconduct against female members who worked for his office and campaign.

In one example of many, Packwood grabbed a female campaign worker’s face in his hands, “pulled her towards him, and kissed her on the mouth, forcing his tongue into her mouth,” according to a Senate report.

Yet the Senate Ethics Committee, then led by McConnell, took nearly three years to delve into the pattern of behavior, leaving Packwood free to remain in office. The panel eventually produced thousands of pages of damning evidence against Packwood and introduced a resolution to expel him.

Packwood resigned first, sparing the Senate from having to take what would have been a painful vote.

House lawmakers are also reluctant to punish their own and rarely expel members. The last lawmaker ousted was Rep. Jim Traficant, D-Ohio, who has forced out in 2002 after a felony corruption conviction that resulted in a lengthy jail sentence.

Looking to counter the impression that lawmakers cannot police themselves, the House in 2008 set up a independent organization, the Office of Congressional Ethics, to accept outside complaints that are required by law to be considered by the internal House ethics panel.

Holman said the OCE has improved ethics oversight in the House, although it’s still rare for lawmakers to issue serious punishment in response to wrongdoing.

Senate lawmakers voted against setting up a similar independent ethics oversight board.

“We have an ethics process that is more or less working in the House, but is not working in the Senate as far as we know,” Holman said.