Follow American politics long enough and you'll start to believe that the Republican party must have some sort of Neville Chamberlain insult generator hidden away in one of the Senate office buildings. (Chamberlain, you may remember, was the British prime minister who infamously came back from a 1938 conference with Hitler in Munich claiming that their agreement, which allowed Hitler to annex a large chunk of Czechoslovakia, had secured "peace in our time." It hadn't.)

After all, it seems like anytime a US president so much as has a conversation with a hostile regime, he can count on being accused of Chamberlain-style "appeasement," or of trying to negotiate "another Munich." Criticism of President Obama over the recent Iran deal is the latest example of the trend, but even Ronald Reagan was repeatedly accused of appeasement during his presidency.

But as this sampling of some of the leaders who have been accused of Chamberlaining shows, this critique is about attitude, not substance. It's trotted out as a way to insist that any leader who is willing to try diplomacy first is nothing but a delusional appeaser, and to imply that aggression is the one-size-fits-all solution to every dispute with an unfriendly regime. That kind of macho posturing might be good politics, but it would make for very bad policy.

The accused: Neville Chamberlain

Who: Neville Chamberlain, prime minister of the United Kingdom from 1937 to 1940.

Reasons for being accused of being Neville Chamberlain: Was in fact Neville Chamberlain.

Accuracy of accusations: Very accurate.

Chamberlain famously tried, unsuccessfully, to avert war by appeasing Hitler with the Munich Agreement. That agreement gave Hitler the Sudetenland, a large chunk of Czechoslovakia. The plan failed spectacularly: Hitler was not satisfied with the Sudetenland, and soon invaded Poland.

Although Hitler was eventually defeated, World War II took millions of lives and left most of Europe in ruins. As a result, Chamberlain and Munich have become political shorthand for politicians' failure to recognize danger, and weakness in the face of it.

However, it's worth noting that many historians now believe Chamberlain was right to sign the Munich Agreement. British historian David Dutton told Slate he believes the evidence was "overwhelming" that Chamberlain couldn't really have done anything differently in Munich, and that he made the best decision possible at the time.

The accused: Ronald Reagan

Who: Ronald Reagan, 40th president of the United States.

Reasons for being accused of being Neville Chamberlain: Negotiated with the Soviet Union.

Accuracy of accusations: Not accurate.

Reagan is now the patron saint of the American right. But during his presidency he was accused of Chamberlain-style appeasement because of his negotiations with the Soviet Union. In 1985 Reagan met with Soviet leader Mikhail Gorbachev at the Geneva Summit, where the two leaders discussed the arms race, the Strategic Defense Initiative (the anti-ballistic missile system also known as "Star Wars"), and human rights. Newt Gingrich called the meeting ''the most dangerous summit for the West since Adolf Hitler met with Chamberlain in 1938 at Munich."

And in 1988, Conservative Caucus Chair Howard Phillips ran an ad that compared Reagan signing the INF arms-control treaty with the Soviet Union to Chamberlain signing the Munich Agreement with Hitler in 1938. "Appeasement Is As Unwise In 1988 As In 1938," said the ad, which showed pictures of Chamberlain, Hitler, Reagan and Gorbachev.

The accusations against Reagan are a clear reminder that the frequent cries of "Munich! Munich! Muuuniccccchhhh!" in American politics aren't really about appeasement: they're just code for "negotiation with dictators we don't like."

It's true that Reagan, like Chamberlain, was negotiating with a hostile power. But Reagan wasn't blind to the threat of the Soviet Union, or responding weakly in the face of aggression — the US was, if anything, the more aggressive party in the arms race at the time.

And, of course, we now know that the Soviet Union crumbled within a few years of Reagan's supposed "appeasement." Reagan's negotiations didn't embolden Soviet aggression; they smoothed the path of Soviet decline.

The accused: Barack Obama

Who: Barack Obama, 44th president of the United States.

Reasons for being accused of being Neville Chamberlain: Willingness to hold talks with Iran.

Accuracy of accusations: Not accurate.

Obama's willingness to negotiate with Iran, as well as with other hostile regimes around the world, has led to a steady stream of Chamberlain comparisons since before he even became president. In 2008, then-President Bush gave a speech in Israel that was a thinly veiled attack on Obama, who at the time was a US senator and presidential candidate, and had argued that the US should hold direct talks with countries like Iran and Syria.

"Some seem to believe that we should negotiate with the terrorists and radicals, as if some ingenious argument will persuade them they have been wrong all along," Bush said in the speech. "We have heard this foolish delusion before. As Nazi tanks crossed into Poland in 1939, an American senator declared: 'Lord, if I could only have talked to Hitler, all this might have been avoided.'"

Get it? A SENATOR? Just like ANOTHER SENATOR WE KNOW?

(Bush's speech also prompted the famously uncomfortable Hardball segment in which conservative radio host Kevin James criticized Obama for being like Neville Chamberlain, but turned out not to have any idea what Chamberlain had actually done.)

The Munich comparisons started cropping up again as the nuclear negotiations with Iran progressed. In 2013, Gingrich said the Iran negotiations were "the Munich of the Middle East,"and that "This is not a negotiation, this is a surrender to the Iranian dictatorship."

And just last week, Republican Senator Mark Kirk compared the negotiations over Iran's nuclear program to Chamberlain's negotiations with Hitler, telling Politico that Chamberlain "got more out of Hitler at Munich" than the Obama administration's negotiators had gotten out of Iran.

Once again, these accusations appear to be based on the idea that any negotiation with a hostile regime is by definition "appeasement," and therefore akin to ransoming the Sudetenland to Hitler.

But while reasonable people may disagree about the deal, comparisons to Munich are so wildly off base that they suggest something is going on here besides a detailed reading of the framework agreement. After all, the agreement seems like it will be very good for the US: the purpose of the agreement is to prevent Iran from getting a nuclear weapon, and experts believe the deal will accomplish that goal. Iran will give up the bulk of its nuclear program and submit to inspections to verify its compliance with the agreement.

That highlights a key point about these kinds of "Neville Chamberlain" accusations: the people making them seem to believe that the lesson of World War II is that the US should never try diplomacy with an unfriendly government — that the mere act of having a conversation is, in and of itself, "appeasement." That position may be appealing in its macho toughness, but in practice it would be a serious, unnecessary limitation on the US's ability to achieve its foreign policy goals.

Angela Merkel and François Hollande

Who: German Chancellor Angela Merkel, French President François Hollande.

Reason for accusation: Failure to respond aggressively to Russian President Vladimir Putin's aggression in Ukraine, including his occupation of Crimea and military assistance for the separatist movement in Eastern Ukraine.

Accuracy of accusation: Moderately accurate.

Last year Russian President Vladimir Putin occupied Ukraine's Crimean Peninsula, and also began providing military and other assistance (including Russian soldiers) to a separatist movement in eastern Ukraine. Western European leaders have responded cautiously, leading to — you guessed it! — comparisons with Chamberlain's response to Hitler.

Merkel and Hollande have taken the lead on peace negotiations with Putin, which hard-liners believe are simply an attempt at appeasing the Russian president's aggression. In February, at the Munich Security Conference, Republican Senator John McCain criticized the European leaders' willingness to negotiate with Putin, saying, "History shows us that dictators will always take more if you let them," and that "they will not be dissuaded from their brutal behavior when you fly to meet them to Moscow — just as leaders once flew to this city."

It is true that there are some worrying parallels between the Munich negotiations in 1938 and the Ukraine negotiations today. Putin has annexed a large chunk of a neighboring country's territory, and at this stage there does not seem to be any serious expectation that he will return Crimea to Ukrainian control. It's not difficult to see how that might be compared to Hitler's takeover of the Sudetenland.

But the core of the Chamberlain/Munich critique is that it didn't work: Hitler signed the agreement and took the Sudetenland but then expanded his European aggression anyway, eventually touching off a massive and damaging war.

In Ukraine, on the other hand, the situation is different. Although Russia has certainly been the aggressor militarily, Putin seems to genuinely believe that the West is conspiring to encircle Ukraine with hostile governments, which suggests that a more aggressive response would only escalate Russian aggression.

And there is little reason to believe Russia will escalate its aggression in the absence of that kind of pressure: Russia's economy has been weakened by low oil prices and targeted sanctions, and the separatist conflict in Eastern Ukraine is dragging on without any clear benefits for Russia. So while Putin's aggression has already been deeply damaging to Ukraine, at this point he seems unlikely to expand it.

In other words, not all roads lead to Munich.