They supported the Iraq war, the bailout of the financial markets and the Bush tax cuts.
Both oppose abortion and same-sex marriage and backed faith-based charities and prayer in public school.
Together, they rank among the most conservative members in Congress.
So are Republican U.S. Senate candidates Jerry Moran and Todd Tiahrt two peas in a pod? How do Kansas voters sort them out prior to the Aug. 3 primary?
Maybe with a microscope.
"They're pretty close," said Jennifer Duffy, analyst for the nonpartisan Cook Political Report.
"We're splitting hairs here," said Kansas State University political scientist Joe Aistrup. "When you look at their voting records, they are incredibly close."
They may be similar, but both candidates are intent on distinguishing themselves, particularly as they duel over the conservatives who tend to turn out in big numbers for primaries.
Tiahrt of Goddard calls himself the race's "one real conservative," and he points to wording in the authoritative "The Almanac of American Politics," which describes him as having a "strongly conservative voting record." The almanac depicts Moran's record as "moderate."
"He votes with the Democrats a lot more than I do," Tiahrt said in an interview. "He likes to go with the wind and with whatever he sees that's popular."
Moran, of Hays, flashes his own conservative bonafides in news releases claiming he is one of only 17 members of Congress to vote against every Washington bailout and stimulus program.
"Our voting records and approach to government speaks for itself," Moran said. "I don't take a back seat to being a fiscal conservative to Todd Tiahrt or most of my colleagues."
His record, Moran said, suggests he votes against bad ideas, whether they be Republican or Democratic.
But congressional records suggest strong uniformity given the thousands of votes both have cast over the years. Tiahrt won his seat in the GOP revolution year in 1994. Moran came aboard two years later.
So far in the current session of Congress, Moran's voted with the Republican Party nearly 96 percent of the time, according to a Washington Post survey. Tiahrt was close behind at 93.1 percent.
Tiahrt recently issued a news release that attempted to draw distinctions between the two by highlighting their ratings from various interest groups. But the differences weren't great: a 100 rating for Tiahrt from National Right to Life, a 96 for Moran; a 94 score for Tiahrt from the U.S. Chamber of Commerce; 91 for Moran.
Tiahrt said the scores made it clear "which candidate has consistently voted for conservative values." Aistrup said the numbers showed just how similar the two are.
"It truly is comical," he said.
But the two candidates have parted company on some key votes that give each candidate bragging rights as to who is further to the right.
For Tiahrt, the argument begins with the sweeping tax cuts proposed by President George W. Bush in his first term. Bush originally sought a $726 billion cut, which Tiahrt supported. Moran was one of just 12 Republicans who opposed it because of the increased spending that went beyond the tax cut and the impact on the deficit.
Both wound up backing the enacted $350 billion cut.
Another example: In 2009, Tiahrt opposed a $32.8 billion expansion of a health care program for children known as SCHIP. Moran backed it.
Moran backed an increase in the minimum wage in 2007 from $5.15 an hour to $7.25 an hour that Tiahrt opposed.
But Moran has his own set of votes that demonstrate a commitment to smaller government. He opposed Bush's major education initiative, No Child Left Behind. Tiahrt backed the bill in the House, then opposed a final version because of changes that affected Kansas.
Moran also split from most other Republicans — and Tiahrt — on Bush's prescription-drug program for Medicare forecast at the time to cost $400 billion over 10 years. Moran voted no, drawing a rebuke from then-House Speaker Dennis Hastert, who had thought that he had Moran's commitment for a "yes" vote.
"Some members had assured me that they would be with us, but when the crunch came, they weren't," Hastert wrote in his 2004 book, "Speaker: Lessons From 40 Years in Coaching and Politics."
One key foreign-policy difference: Moran favors closer trade ties with Cuba, saying U.S. policy toward the island nation has failed. Tiahrt does not, saying a better trade relationship would only bolster the Castro regime.
In 2006, Moran was one of just seven Republicans who opposed a bill sanctioning military tribunals to try suspected terrorists, and he also opposed a bill granting legal status to President Bush's warrantless wiretapping program. He said he feared both programs granted too much power to the government.
Tiahrt voted for both.
On earmarks — the pet spending projects for individual members of Congress — Moran has supported reform and a reduction in their numbers. Tihart is known as an earmark defender and, in 2008, reportedly opposed GOP leaders who had proposed a temporary earmark moratorium.
Moran and Tiahrt also split on the DREAM act, which is legislation pending in Congress that would open the door for students to earn citizenship through college or military service. Moran has opposed the idea while Tiahrt once co-sponsored the legislation. Tiahrt now calls that a mistake.
On the larger issue, Tiahrt has supported a temporary job permit program that would require illegal immigrants to register to continue working and pay taxes. "After that, they must return to their country of origin," Tiahrt wrote in The Wichita Eagle in 2006.
Moran said he opposes giving legal status to undocumented workers.
Question of style
So how will voters make decisions in this race? It could come down to a question of style.
Tiahrt brands himself as a fighter who will go to the mat for Kansas interests.
"To me you want somebody who will stand their ground and do what's necessary to do, to provide a recovery for our economy and opportunity for our future," Tiahrt said.
He said he's met "nobody" in Washington who thinks Moran is a fighter.
Moran isn't buying it. Speaking loudly and pounding on tables isn't enough, he said.
"It's about being able to accomplish things," said Moran. "I'm very proud of a record that demonstrates the ability to get things done."
Aistrup said Tiahrt "wears his conservatism on his sleeve a bit more. Jerry tends to be more laid back and traditionally a little bit more modest in his approach. Nevertheless he's very conservative in his voting record.
"It's a matter in which way voters want to see their views represented in Congress."
Washburn University political scientist Bob Beatty regards Tiahrt as more confrontational. Moran is folksy, with an approach that says: "You can trust me; you know who I am."
Both candidates will be looking for contrasts in the weeks ahead, and that could result in a sharper tone.
"The candidates have to differentiate themselves," Beatty said. "One way to do that is to point out negative characteristics of the other."