Sen. Bob Casey (D) led his opponent, former coal company owner Tom Smith (R), by 10 points in a new Philadelphia Inquirer survey released today.

Casey scored 48 percent, while Smith had 38 percent, in the bipartisan poll.

These new numbers represent the first-term Senator’s strongest lead in a public poll during the last month. Other recent surveys showed a much tighter race — although

 — although some of those polls were from firms such as Susquehanna Polling and Research,

of those polls were from firms such as Susquehanna Polling and Research, which often works with Republicans.

Still, as the Inquirer noted, Casey’s margin has been cut in half since its August poll. He’s also fallen under 50 percent.

Roll Call rates this race as Likely Democratic.

Global Strategy Group, a Democratic firm, and National Research Inc., a GOP firm, conducted the survey of 600 likely voters Oct. 4-8. The margin of error was 4 points.