However, the main reason why Labour has found it hard to mount a convincing assault is that the Tory plans to restrain public-spending growth are so modest.

ECONOMIST: Spending plans

California Rep. Mike Thompson told CNN on Tuesday that a ban on high-capacity magazines could garner Republican support, but a full-scale assault weapon ban would be hard to get passed in the GOP-controlled House.

CNN: GOP balks at Obama's post-Newtown gun control proposals

These moves may seem small-bore compared to gun laws in many other countries, but they are a very big deal here, and it is hard to see how the ban on assault rifles will get past Republican (and indeed some Democratic) opposition in Congress.

BBC: President Obama's next campaign - against the gun lobby