Still, with 535 members of Congress attending the joint session, the number of those who have committed to the new display of comity are a relatively small fraction, with some insisting they'll sit where they always have; among members of their own party.
"If people want to mix it up, they certainly can. We don't have seating assignments for most of our members," said Senate Minority Leader Mitch McConnell, who has said he will not be sitting on the left side of the aisle, in an interview on Fox News.
"More important than the appearance of sitting together is what we do together. And the American people are more interested in actual accomplishments on a bipartisan basis here in the next six to nine months than they are with the seating arrangement at the State of the Union."
McConnell and other GOP aides have noted that lawmakers have always been free to sit where they want and that this year is no different. Seating for the speech is first come, first served, and it's likely many members will be sitting next to colleagues of the opposite party whether they want to or not.
House Speaker John Boehner and House Minority Leader Nancy Pelosi have not yet weighed in publicly on the seating proposal. Senate Majority Leader Harry Reid has only said that the plan should receive "serious consideration."
A recent CNN poll found more than 70 percent of Americans support mixed seating of Republicans and Democrats for the State of the Union address.
ABC News' Matthew Jaffe contributed to this report.