Incumbent Senate Republicans should be prepared for a "new political landscape" in 2012, their campaign committee chairman said Monday.

Sen. John Cornyn (R-Texas), the chairman of the National Republican Senatorial Committee, put GOP senators on notice that they should be prepared to fend for themselves in contested primaries.

"Every incumbent needs to be prepared in their own right in a primary," Cornyn said during an appearance on MSNBC.

"I think people who have been in the Senate for a while, they're going to encounter a whole new political landscape in 2012, much as our candidates did in 2010," he later added.

The second-term NRSC chairman's comments serve notice to some of the longtime GOP incumbents who are up for reelection in 2012 that they should be bracing themselves for a possible primary challenge along the lines of what their colleagues faced in 2010.

Both Sens. Bob Bennett (R-Utah) and Lisa Murkowski (R-Alaska) lost their primaries this past election cycle to activist, conservative Tea Party candidates. (Murkowski ran as an independent write-in candidate and won reelection.)

In other contests, more establishment-friendly Republicans recruited by the NRSC lost primary battles against Tea Party candidates, who went onto mixed records on Election Day.

Republicans made some "poor choices" when it came to Senate candidates that prevented even greater wins, Sen. Lindsey Graham (R-S.C.) said over the weekend. But incoming House Speaker John Boehner (R-Ohio) said the GOP's relationship with the Tea Party helped the party avoid a "shellacking."

Cornyn noted that senators who, for instance, voted against a ban on the practice of earmarking shouldn't be surprised if they face a primary in two years.

"We have a new political reality where earmarks have become a symbol of wasteful Washington spending," he said, noting that sentiment was strong "particularly in Republican primaries."