Perhaps out of fear of a grassroots insurrection, six conservative senators sent a letter to Harry Reid today expressing a newfound concern about the PROTECT IP Act.

Via Lachlan Markay at The Foundry:

Sens. Chuck Grassley (R-IA), John Cornyn (R-TX), Orrin Hatch (R-UT), Jeff Sessions (R-AL), Mike Lee (R-UT), and Tom Coburn (R-OK), sent a letter to Senate Majority Leader Harry Reid (D-NV) on Friday expressing their concerns.

The letter, whose signatories include the ranking Republicans on the Budget, Finance, and Judiciary Committees, warns of “breaches in cybersecurity, damaging the integrity of the Internet, costly and burdensome litigation, and dilution of First Amendment rights” could result from passage of the hotly-contested PROTECT IP Act.

Still, the Senators didn’t go so far as to actually condemn the legislation, they just say it deserves further scrutiny. They do, however, explicitly mention the “large number of constituents and other stakeholders with vocal concerns about the potential unintended consequences of the proposed legislation.”

Sens. Rand Paul and Jerry Moran have voiced opposition to the bill in the past, but these six heavyweights voicing their reservations represents a horse of another color. The floor debate on this one should be really interesting (it comes up on Jan. 24th, for the C-SPAN crowd), and there’s definitely a conservative case to be made against the bill – it could force companies to stop doing business without due process, it’s anti-competitive and blatantly violates free speech. But opposition to the bill isn’t just principled, it’s also good politics – grassroots opponents to SOPA and PROTECT IP are proving to be numerous and extremely vocal, especially among the Tea Party. Not only that, but with all the Hollywood money being funneled into the Democratic Party, Harry Reid can’t afford to look less than solicitous of their interests.

As Matt Lewis noted today, important philosophical battles are going on on the right today, especially compared to the left.

While Democrats are essentially falling lockstep behind President Obama, Republicans are engaging in some very important philosophical debates. For example, the rise of Ron Paul demonstrates that the GOP includes both hawks and a large number of non-interventionists. The schism over Bain Capital demonstrates the cleavage between the big business wing of the Republican Party and the more populist conservative strain.

I suppose the SOPA/PROTECT IP debate falls roughly within the latter. But in this case the populist conservatives are aligned with some of the biggest and most innovative tech companies including Google, Facebook and Twitter. Passing SOPA wouldn’t be a victory for free markets, it would be a victory for the narrow special interests that pushed for it.