Categorically.
"Modern conservatism" is an oxymoron. It's absolutely identical to the brand of laissez-faire conservatism of the late 19th century and damned near dead on for the form of late 18th century monarchical conservatism that our founding fathers rebelled against. In fact there are so many precedents in history for southern conservatism (modern conservatism as your calling it) that it aint even funny. You essentially represent the type of oligarchical conservatism that dates back to the ancient Roman Republic. You're kidding your self to think that southern conservatism even remotely compares to the ideals of the American Revolution. I mean that's just plain laughable!
You focus only on the economic aspect of the more extreme neocon movement. Many correctly point out that conservatives have become factionalized today, and laissez-faire is one of the reasons. The mainstream conservative movement of today supports reasonable regulation of business, but draws the line of acceptable regulation to a far more limited role than today's liberal.
But there are other aspects of the conservative philosophy in addition to (some would say more important than) economic policies, such as severe limitation of government, minimal taxation, putting people's rights above government purpose, adhering to the word of the Constitution, being willing to suggest the possibility of armed revolt, and demanding the maintenance of those constitutional rights if such a need becomes real.
I do not see the average "liberal" of today supporting any of the principles of the founders with the sole exception of being (verbally) opposed to oligarchical type economic structures (while in reality supporting a policy of bolstering the failed oligarchical structure with taxpayer money). The liberalism of today is unrecognizeable compared to the liberalism of the founders.
Both Thomas Jefferson and Alexander Hamilton, who were on opposing sides with regard to federalizing under the Constitution, would have vehemently opposed the economic policies of today's liberalism. They would have been horrified to be associated with the centralized, massively intrusive federal government supported by today's liberal philosophy. Jefferson would likely have advocated shooting a federal court justice who thinks it is her job to "set policy". I hate to think what they'd have to say to the "reasonable gun laws" gun grabbers.
I do not agree with the extreme degree of laissez-faire conservatism is leaning in economic matters. However I also disagree with the even more extreme degree liberals lean on economic matters.
I do agree with the principles, supported by today's conservative faction and opposed by today's liberal faction, of returning to a Constitutionally limited federal government, paying a whole lot more attention to the Bill of Rights, including both the 9th and 10th Amendments.
I disagree with the modern liberal principle of "reasonable limits" placed on constitutional rights via preemptive regulation and laws. The "limits" of a right is simply that one may not deliberately or knowingly cause harm to another then hide behind constitutional protections to avoid responsibility for their harmful actions. "Reasonable" limits on rights by written law is the exact action of government the BOR was written to prevent, yet a policy fully supported by modern liberals.
In short, the laissez-faire economic faction of today's conservative movement are counter to the views of the founders - who were, indeed, revolutionary liberals by definition (But NOT "extreme leftist" by today's definition of left v right) on that specific issue. However, the modern liberal movement of today support not only economic principles counter to the founders, but also views of federalism, centralized economic authority, "limited" rights, etc. that are quite the opposite of the principles which were used when writing the Declaration of Independence, the Constitution, and (especially) the Bill of Rights.
