The recently concluded Republican and Democratic party conventions offered an astonishing role reversal in American politics.

Under Donald Trump, Republicans painted a dark and ominous view of the United States, almost entirely devoid of optimism, national pride and the familiar tropes of American patriotism. Astonishingly, it was the Democrats who seized control of the Reaganesque messages of American exceptionalism, national pride and these patriotic symbols.

Since the Vietnam War, it has traditionally been Democrats who have presented themselves as the party that says “yes, but” to patriotism. But now Democrats have embraced the American civic religion in a smothering bearhug.

Under Mr Trump, however, Republicans have presented their fellow Americans with an utterly dystopian perspective in which the country is facing an almost apocalyptic crisis and there is only one man who “alone” offers a way out.

Yet Mr Trump goes much further than any national Democratic figure has ever gone in criticising United States and embracing its international opponents. Most notably he encouraged Russia to engage in cyber espionage by hacking Mrs Clinton’s emails. He later tried to say that he was joking, but nobody believes that.

Unfortunately, what the comments demonstrate is that he simply has no idea what kind of line he is crossing and why it exists. He is a highly privileged, uninformed amateur who is used to saying anything he likes without consequences.

He said Washington is in no position to criticise other countries like Turkey for human rights violations, and called the American military “a disaster”. His consistent, fulsome praise of Vladimir Putin is not only astonishing, it’s inexplicable, except for the fact that he is posing as an American version of Mr Putin.

Mr Trump’s statements are not only un-American, in the sense that they are an unprecedented, radical breach of the country’s long-standing foreign policy consensus. They are downright anti-American, in that they are so willing to criticise the present American condition that they are sometimes actually hostile to the United States.

Republicans under Mr Trump are now the party saying “yes, but” to American nationalism, not the Democrats. This extraordinary role-reversal raises two key questions. First, although Democrats clearly won the battle of the conventions and have seized control of the symbols of patriotism, it might not matter. It is unlikely but possible that Mr Trump’s asymmetrical political warfare has so altered the political playing field that Democrats have just won a battle that no longer determines the outcome of the conflict. They are pursuing conventional political warfare, while he is using guerrilla tactics and sabotage. So it is just possible that what would normally be an unstoppable political victory could, bizarrely, prove irrelevant.

Second, not only could the Democrats win, but they also might win in a colossal landslide if the public fully comprehends what the dangerous and ultimately unacceptable risks of a Trump White House truly are. Moreover, there is the potential for a massive political realignment in the works.Many establishment Republicans are now reduced to hoping that Mr Trump will lose a close election without damaging Republican chances of retaining control of Congress. But they have taken such an extreme gamble that Republicans might end up losing it all, just as they did after the fiascos of Hurricane Katrina and the financial meltdown at the later stages of the George W Bush administration.

Large numbers of national security voters, internationalists, foreign policy hawks and neoconservatives are resigned to voting for Mrs Clinton in spite of their long-standing Republican affiliations. Many of them also bolted from the Republican Party and voted for Barack Obama in 2008 after John McCain selected the absurd Sarah Palin to be his running mate.

Now they are preparing to do the same thing and support Mrs Clinton. Is it possible that they will feel tired of continuously bolting from the Republican Party? In the late 1970s and early 1980s, many liberal hawks abandoned the Democratic Party and joined the Republicans, forming the nucleus of the neoconservative movement. The same thing may be happening in reverse today. We might soon see wide-scale defections of internationalist and national security figures from the Republican Party, which is consistently no longer providing an acceptable home for them, to the Democrats.

Of course Republican Party leaders are hoping that after he loses the Trump phenomenon will simply evaporate. But what about the countless millions in their base who have embraced Mr Trump and rejected them?

Even if he loses, putting that genie back in the bottle may be very difficult, if not impossible. The election and its aftermath will answer both questions. If normal American politics prevail and Mrs Clinton wins, Republican leaders will try to piece their traditional, recognisable party together again. And depending on how successful they are, they may not be able to retain the loyalty of many whose politics are structured around national security and patriotism, especially given that they keep having to vote for the Democrats anyway.