Members of both parties photographed on the Senate floor last July. (Associated Press)

Most congressional observers agree that the level of discourse on Capitol Hill is coarser and more partisan than ever before. A new study suggests it’s also dumber.

Congress collectively speaks at almost a full grade-level lower than it did seven years ago, with Republican lawmakers ranking as the smartest and least-smart-sounding talkers, according to a new study by the Sunlight Foundation sure to earn the ire of at least some congressional offices.

The study rightfully notes that what some might consider “the dumbing down” of congressional speeches could be interpreted as an attempt to more simply and effectively communicate with constituents. That effort could be in part because the study says that Congress generally speaks at a higher grade level than average Americans.

Using the Flesch-Kincaid test, which equates higher grade levels with longer words and sentences and higher numbers of syllables and characters, the study concludes that lawmakers speak at a 10.6 grade level, down from 11.5 in 2005. Americans generally speak at between an 8th and 9th grade level.

That’s an impressive level of discourse, but lower than some of the country’s greatest oratory hits. The U.S. Constitution, for example, ranks at a 17.8 grade level; the Declaration of Independence earns a 15.1 grade level; the Gettsyburg Address comes in at 11.2; and Martin Luther King Jr.’s “I Have a Dream” speech weighs in at a 9.4 grade level.

A similar study conducted for the last three years has found that President Obama’s State of the Union addresses ranked at roughly an 8th grade level — some of the lowest rankings of the last 70 orally-delivered State of the Union speeches.

So which lawmakers are the top and bottom speakers? Here’s how the Sunlight Foundation ranks ‘em. Share your thoughts in the comments section below:

Bottom Congressional Speakers:

1.) Rep. John “Mick” Mulvaney (R-S.C.): 7.95 grade level

2.) Rep. Rob Woodall (R-Ga): 8.02

3.) Sen. Rand Paul (R-Ky.): 8.04

4.) Rep. Sean Duffy (R-Wis.): 8.09

5.) Rep. Tim Griffin (R-Ark.): 8.13

6.) Rep. Todd Akin (R-Mo.): 8.14

7.) Rep. Vicki Hartzler (R-Mo.): 8.44

8.) Rep. Tom Graves (R-Ga.): 8.60

9.) Rep. David Schweikert (R-Ariz.): 8.61

10.) Sen. Ron Johnson (R-Wis.): 8.62

Top Congressional Speakers:

1.) Rep. Daniel Lungren (R-Calif.): 16.01

2.) Rep. Lucille Roybal-Allard (D-Calif.): 14.94

3.) (tie) Rep. Jim Gerlach (R-Pa.): 14.19

3.) (tie) Rep. Thomas Petri (R-Wis.): 14.19

5.) Sen. Daniel K. Akaka (D-Hawaii): 14.18

6.) Rep. William “Mac” Thornberry (R-Texas): 14.13

7.) Sen. Olympia Snowe (R-Maine): 14.02

8.) Rep. Rodney Alexander (R-La.): 13.94

9.) Rep. Mark Amodei (R-Nev.): 13.83

10.) Rep. Ralph Hall (R-Texas): 13.74

Follow Ed O’Keefe on Twitter: @edatpost

More from PostPolitics:

Axelrod scolds Booker on Bain

Catholic groups sue Obama administration

Justices pressured to reconsider Citizens United case