By Jim Puzzanghera, Los Angeles Times

WASHINGTON — Lawmakers in Congress are voting more often along party lines. But within the ranks of Republicans, there is growing evidence of voting along age lines.

The generational split, fueled by a surge in young lawmakers who won seats in recent elections, has been emerging on a number of tax and spending bills, including last year’s transportation funding bill and this year’s pending farm bill.

And that divide may be deeper even than differences over Tea Party issues, now that most Republicans in Congress are conservative.

“Clearly, as a group, the younger members coming in the last two or three classes have been more ideologically conservative … than most of the older members,” said Norman J. Ornstein, a congressional expert at the American Enterprise Institute, a Washington think tank.

The tension between young and old was on display at a recent Senate committee hearing over technology companies stashing hoards of cash offshore to avoid paying income taxes on profits earned overseas.

Sen. John McCain, R-Ariz, 76, criticized Apple Inc. for using foreign subsidiaries to avoid paying billions of dollars in U.S. taxes. But Sen. Rand Paul, R-Ky., 50, defended Apple as “a great American company” simply trying to find legal ways to minimize its tax bill.

No legislation, however, has brought the generational divide into focus more clearly than the Internet sales tax bill, which would allow states to require larger online retailers to collect sales taxes from customers as bricks-and-mortar merchants must do.

Senate Republicans split nearly evenly on the legislation, with most older members supporting it and younger ones in opposition.

“Every single Republican under the age of 50 voted against this bill in the U.S. Senate, and I think it has a great deal to do with being part of the Internet age,” said freshman Sen. Ted Cruz, R-Texas, 42, a Tea Party favorite. “We should not be messing with the Internet.”

Like most of his older Republican colleagues, Sen. Mike Enzi, 69, who owned three small shoe stores before entering politics in the 1970s, sympathizes with conventional retailers who want to end the nation’s long online sales tax holiday.

As a former mayor and state legislator, he also knows that states and local municipalities need to collect sales taxes to bolster their budgets and help keep the roads in repair and the sewers working.

“It is pretty hard to flush your toilet on the Internet. Those taxes are very important to almost all of the communities across the United States,” said the Wyoming Republican, who helped pass the Marketplace Fairness Act in the Senate.

Freshman Rep. Thomas Massie, R-Ky., 42, like Cruz one of the young Turks in Congress, opposes the legislation as a threat to e-commerce and an expansion of state taxing powers.

“All of my post-college life has been in a world where the Internet has been a ubiquitous part of our lives,” Massie said.

The opposition of young members such as Massie has left the bill’s fate unclear in the House, where the average age of lawmakers is five years less than in the Senate.

“Younger generations are more e-commerce-oriented,” said Rep. Steve Womack, R-Ark., 56, the leading Republican sponsor of the House legislation. “The House is a younger bunch … and that may contribute to the fact that it’s harder to get younger members on board.”

Veteran lawmakers — that is, older ones — are more inclined to support conventional retailers arguing for a level playing field and to back their state and local officials, who want to generate more revenue without raising tax rates.

Younger members, many of whom are Washington newcomers, tend to back Internet companies such as online auction site EBay Inc. in opposing the measure as an undue burden on online retailers and an expansion of a state’s taxing authority outside its borders.

“I think there is a bit of a divide in Congress between those who understand the potential the Internet has to revolutionize the way we do commerce in this country and those who are trying to protect special interests,” said Evan Feinberg, president of Generation Opportunity.

The libertarian group, which represents young people, launched a protest on Enzi’s Facebook page against the Internet sales tax legislation.

“I applaud that he was a small-business man before he entered public service,” Feinberg said of Enzi. “It’s just that commerce has changed dramatically since he owned that shoe store in 1974.”

Older lawmakers frequently have been criticized for not being technologically savvy. In 2006, then-Senate Commerce Committee Chairman Ted Stevens, R-Alaska, at 82, was mocked by bloggers for a rambling speech in which he described the Internet as a “series of tubes.”

In the last few years, Congress has seen a flood of younger lawmakers.

The average age of newly elected senators dropped to 53 this year from 57.1 in 2009, according to the Congressional Research Service. The average age of new House members dropped to 49.2 this year from 49.8 in 2009.

In the online sales tax debate, the average age of Republican senators who voted in favor of the bill in May was 64, according to an analysis by Heritage Action for America, a conservative advocacy group. The average age of Republican senators who voted against the bill was 58.

The group noted that 12 of 13 Senate Republicans ages 55 or younger opposed the legislation.

Overall, 22 Senate Republicans voted for the bill and 21 opposed it. The legislation passed 69 to 27, with most Democrats voting for it.

Sen. Kelly Ayotte, R-N.H., 45, who is not in the Tea Party caucus, said she hadn’t thought about why younger Republicans like her were more likely to oppose the bill. She voted against it because the legislation clashed with her conservative philosophy that government should be smaller and more limited.

Massie, the young congressman from Kentucky, said he thought the generational split on the Internet sales tax and other issues reflected more skepticism among newcomers about Washington’s ways.

“It may be that the younger folks haven’t been here as long,” he said. “They’re still in touch with their constituents and less with the constituency inside the beltway — the lobbyists.”

David French, senior vice president for government relations at the National Retail Federation, said that many of the Senate Republicans who opposed the legislation did not have experience in state government.

“It’s not about technology versus the old way of doing things,” said French, whose group has been lobbying for the legislation. “I think this is a lot more about the callow inexperience of youth.”

It will take some time to build support in the House, and a lot of small retailers will be contacting their lawmakers over the next few months to push for the legislation, he said. The trade group includes small retailers and large ones, such as Wal-Mart Stores Inc.

Rep. Peter Welch, D-Vt., one of the leading backers of the legislation, rejected the idea that supporters, regardless of party, did not understand the Internet.

“I guessed I’d be on the older side, but I certainly appreciate the immense benefit of the Internet and how important it is in commerce,” said Welch, 66. “But this in no way is going to inhibit the Internet.”

Enzi agreed.

“I’m encouraging every businessman I know to make sales on the Internet,” he said. “But they need to help follow the law, which is to help collect the sales tax that’s due.”