Donald Trump supporters clash with police and security forces as people try to storm the US Capitol on Jan. 6, 2021. (Getty images)

The United States is closer to civil war than any of us would like to believe, warns Barbara F Walter, a political science professor and member of a key CIA advisory panel.

No one wants to believe that their beloved democracy is in decline, or headed toward war, Walter writes in a new book, How Civil Wars Start, due to be published in January, according to The Washington Post.

Walter, who sits on the Political Instability Task Force, argues that if you were an analyst in a foreign country looking at events in America, you would find that the United States has entered very dangerous territory.

The analysis comes amid growing concerns about the deepening political divide in the United States, which was exacerbated by the events that marred the 2020 presidential election.

The claim by former President Donald Trump and his allies that he lost the 2020 election to Joe Biden because of mass electoral fraud stoked the deadly assault on the Capitol building on January 6.

Trump was subsequently impeached for inciting an insurrection and acquitted a second time, leaving him free to run for president again.

Encouraged by the developments, Republicans are taking steps to restrict voting by groups that lean Democratic in an effort to make it easier to overturn election results in the future. That has many experts worried that another insurrection or even civil war is likely in 2024.

Walter noted that that the United States has moved through stages of pre-insurgency and incipient conflict and may now be in open conflict in the wake of the Capitol riot. She also says the US has become an anocracy - somewhere between a democracy and an autocratic state.

Last month, Walter warned in a tweet that the CIA is focused on tracking conflict trends abroad, leaving the United States essentially blind to worrisome developments at home.

Walter is not alone in her analysis of the situation in the United States.

Three retired US army generals have sounded the alarm about the deepening political divide in the United States, warning about the possibility of a civil war after the 2024 presidential elections.

Former Major Gen. Paul Eaton, former Major Gen. Antonio Taguba, and former Brig. Gen. Steven Anderson made the warnings in an op-ed in The Washington Post on Friday.

As we approach the first anniversary of the deadly insurrection at the US Capitol, we - all of us former senior military officials - are increasingly concerned about the aftermath of the 2024 presidential election and the potential for lethal chaos inside our military, which would put all Americans at severe risk, they wrote.

The generals cautioned about potential turmoil in US armed forces, citing the disturbing number of veterans and active-duty members of the military that participated in the Capitol attack -- more than 1 in 10 of individuals charged in connection with the riot had a service record.

Without constant maintenance of order, a riot within the military, reflecting discord in society, is quite real, they asserted.

The generals outlined a scenario in which some service members might choose to pledge loyalty to a presidential candidate who refuses to concede defeat, as Trump did in 2020. Under such a scenario, it is not outlandish to say a military breakdown could lead to civil war, they wrote.

Since the November election, the US armed forces have been mired in turmoil and division along partisan lines, the generals said, citing the increasing resistance within the ranks towards federal COVID-19 vaccine mandates.

The potential for a total breakdown of the chain of command along partisan lines - from the top of the chain to squad level - is significant should another insurrection occur. The idea of rogue units organizing among themselves to support the ‘rightful’ commander in chief cannot be dismissed, they warned.

The generals advised that all measures be taken to ensure another insurrection does not occur, including by holding to account leaders who inspired the Jan. 6 riot.