(CNN) - The rule of threes was validated on Tuesday when Iowa Republican Rep. Tom Latham announced he would not seek re-election to his House seat in 2014.
Earlier in the day, Virginia GOP Rep. Frank Wolf and Utah Democratic Rep. Jim Matheson also said they would not run again.
Latham, 65, a close friend and ally of House Speaker John Boehner, shared his decision in a message to supporters.
"It is never a perfect time or a right time to step aside. But for me, this is the time," he said.
First elected in 1994, the Iowa Republican is a senior member of the House Appropriations Committee and won his 10th term in 2012 in a tough race after his seat was redrawn to overlap with Iowa Democratic Rep. Leonard Boswell.
Latham ended up beating Boswell, 52% to 44%.
Earlier this year, Democratic state Sen. Staci Appel announced she would challenge Latham and many expected another competitive midterm contest in 2014.
Iowa's 3rd Congressional District encompasses parts of the Democratic-leaning Des Moines area and the Republican-leaning southwest counties along the Nebraska and Missouri borders.
President Barack Obama won Latham’s district with 51% of the vote in 2012.
When Sen. Tom Harkin announced he would not seek re-election earlier this year, Latham considered running to replace him but ultimately decided against a two-year campaign.
The Democratic Congressional Campaign Committee said it sees Latham’s seat up for grabs.
“The mass exodus of Republicans fleeing John Boehner’s dysfunctional House is putting more and more competitive districts into play every day,” DCCC chair Steve Israel said in a statement.
“Democrats will demonstrate to voters in this toss-up district that we’re committed to making a difference in their lives, whether it’s by passing a farm bill or moving forward with an agenda to strengthen and expand the middle class.”
The House GOP campaign chief, Rep Greg Walden, R-Oregon, released a statement praising Latham, but also predicting the seat would remain in GOP's hands.
"Iowans have been well served by having one of the hardest working members as their representative in Congress. I am confident that they will elect a Republican to represent this district next November," Walden said.