All of this reading would be pricey if you were buying the volumes, but if you are a university alumnus, you might check with them to see if you have access to their library. I've also bought a community library card from my local university. You can also speak to your local public librarian about getting inter-library loans. JASNA Canada has an online catalogue of books about Jane Austen and you can borrow from them if you are a member.
Here are three scholarly books that I've found worthwhile:
Collins also discusses the "restraint which Jane Austen felt in speaking and writing about religion" arising out of "austerity of Anglican worship at the time." The differences with evangelists were not just around doctrine, but around modes of worship. (More on that restraint here).
I found the last three chapters to be the most valuable. "Manners and Morals," "Morals and Society" and "Worship and Belief" contain reflections on Austen's novels and what they reveal about her personal morality and her world view. Collins canvasses the influential thinkers of the day such as Wilberforce, Burke and Locke, and the influence of the Evangelicals versus Church of England traditionalists.
Collins places Jane Austen on the side of the traditionalists. Austen's portrayals of feckless estate-owners like Sir Walter Elliot are not a veiled call for revolution, but an illustration of what happens when people don't live up to their responsibilities. Collins says: "Austen refused to regard the financial difficulties widespread among the gentry as due to anything but mismanagement: Colonel Brandon can soon put to rights the encumbered estate he inherited from his profligate brother and Sir Walter Elliot could have stayed at Kellynch if he had been prepared for modest retrenchment." Later, Collins notes that Austen gives credit where credit is due to merit regardless of birth: "she was by no means hostile to change. Admiral Croft turns out to be a better tenant for Kellynch Hall than Sir Walter Elliot of ancient lineage -- better for the grass, the sheep, the poor and the parish, as well as the house."
And for much more on the clergy, the church, and the role of religion in Austen's time, try also Brenda S. Cox's book, Fashionable Goodness (2022).
As I have (ahem) frequently mentioned in this blog, I don't think Austen held radical views for her time. Isn't it interesting that scholars can sift and weigh the same evidence and come to completely opposite conclusions!
I think on the evidence, Roberts is right; Austen's a Tory in a Tory family and she's proud of her sailor brothers who served King and Country. She was not itching to send the aristocrats to the guillotine. But some issues, such as the abolition of slavery, crossed party lines, so a label can sometimes be limiting.
I think the most useful way to ask if Austen is making subtle and veiled allusions to the French Revolution (if this is really a question that exercises you) is to compare her books with the novels of her contemporaries who do bring politics more overtly into their novels. There are novelists who were much more outspoken, pro and con, about the French Revolution. For example, in Consequences or Adventures at Rraxal Castle (1796), young Lord Oswell comes back from a trip to France as a confirmed Republican. He addresses his noble father as "citizen." Oswell comes to a bad end. In this book, you don't have to read deep between the lines, as Roberts does with Austen. I think the question should be, "she was referencing the French Revolution compared to whom?"
John Sutherland, in Is Heathcliff a Murderer?: Great Puzzles in Nineteenth-Century Fiction, makes fun of Roberts. He says: "Roberts' line goes thus: "as is well known, Jane Austen never mentions the French Revolution. Therefore it must be a central preoccupation, and its silent pressure can be detected at almost every point in her narratives." Yes, it's all the more powerful for being completely unstated. This is exactly what's going on today with "interrogating" Austen to unearth her views on slavery.
However, I agree that Roberts tends to read too much significance into little things. For example, when Henry Tilney scolds Catherine Morland for her gothic imagination, he says that the neighbourhood is full of voluntary spies. Roberts thinks that "spy" sentence jumps out of Henry Tilney's speech to Catherine. He thinks the reference to spies must make us think of government spies, and it must be quite a loaded word. Austen also uses the word in Mansfield Park. Mrs. Norris thought Susan was "a spy, and an intruder, and an indigent niece, and everything most odious." People used some words in contexts we wouldn't use today, including "plantation" (it meant, place that is planted), "slave" ("Your mother must have been quite a slave to your education") and "race" (Austen uses this word to describe the Morlands, instead of just "family."). So "plantation" and "race" don't have the same dark connotation for people in Austen's time that they do for us.
Roberts at least reads the "dead silence" passage in Mansfield Park correctly. Sir Thomas was not silent, it was his daughters. I think Roberts is solid in what he says about Mansfield Park. Similarly to Tony Tanner, he says the novel is about a traditional way of life that comes under threat because the people in charge of that traditional way of life (Sir Thomas and Lady Bertram) fail to guard it from dangerous interlopers (the Crawfords) who are alluring and attractive but dangerous and wrong. He also puts a charitable construction on whatever it was Sir Thomas was doing in Antigua, but it is all speculation in the end.
Jane Austen and the French Revolution is filled with useful historical information and cross-references to Austen's books and letters, and I think it's more accessible and readable for an introduction to the question of Austen's political views than Marilyn Butler's Jane Austen and the War of Ideas. I'd read this one first, then go on to Baker, if this topic is of interest to you.
Now that her rivals have dropped away into obscurity,* Austen and her work stands alone, and the modern reader does not have the benefit of understanding the milieu Austen grew up in, and the way her novels made a contribution to a national conversation. For example, many people wonder why it was such a big deal that young people would entertain themselves by putting on a play in a country house. Butler says of Lover's Vows, the play featured in Mansfield Park: "modern commentators sometimes underrate how notorious it was; how critics and satirists from the Anti-Jacobin (journal) had made it a byword for moral and social subversion."
Butler points out that Austen is not a revolutionary in terms of her ideas. She revolutionized the novel. "Her important innovations are technical and stylistic modifications within a clearly defined and accepted genre."
And while Austen's novels can be studied in the context of the "War of Ideas," they are also novels about people who go through crises and suffer and redeem themselves from their errors. The plots revolve around how Darcy overcomes his pride, Elizabeth overcomes her prejudice and Emma realizes she's been deluding herself and hurting other people.
I read this book in short doses with a highliter in my hand, and I think I'll refer back to it again and again to really absorb all the ideas and information presented.
*(Even the best known of them, like Burney and Radcliffe, have a small readership today compared to Austen).