Charles Boustany and John Fleming are both doctors, both Republicans and both congressmen from Louisiana.

In the grand scheme of things, they are not that far apart politically: Both are strongly conservative. But within the philosophical confines of the House Republican membership, there is some daylight between them.

Boustany, first elected in 2004, is regarded as a “team player” who generally cooperates with the House Republican leadership and is comfortable with government playing a role in society. Fleming, first elected in 2008, is more of an ideological purist in the tea party vein: He is a founder of the House Freedom Caucus, a group organized this year to push House Republicans further to the right.

One way Boustany and Fleming may well differ is on the question of who should succeed Republican David Vitter in the U.S. Senate, should Vitter win election as governor this year. Fleming has declared he wants the job; Boustany has not announced his intentions but is widely considered to share an interest in the seat.

A clear difference between them, highlighted last week, is over foreign trade and, specifically, the request by Democratic President Barack Obama for “fast-track” negotiation authority on trade agreements — in particular, the Trans-Pacific Partnership under discussion.

Fast-track authority empowers the president to work out a trade deal and present it to Congress for a straight up-or-down vote. The authority has been provided to both Democratic and Republican presidents going back to 1974, but it expired in 2007. Fast-track supporters argue that without it, trade agreements would be nearly impossible to negotiate, because other countries would worry that Congress would tear apart any deal and push for new concessions.

Obama wants to apply the authority most immediately to the forthcoming TPP, which would lower barriers to trade among the United States, Japan, Malaysia, Vietnam, Singapore, Brunei, Australia, New Zealand, Peru, Chile, Mexico and Canada.

TPP supporters say it will open foreign markets, boost U.S. exports and create high-paying American jobs in companies that trade with the affected countries. Opponents say it’s American jobs that will be exported, to countries with lower wages, and that the pact will enlist the United States in a “race to the bottom” that will degrade food safety and environmental protection.

Fast-track authority and the TPP are linked, politically, and the debate over them breaks down along unusual lines. Business interests and most Republicans support the proposals. Labor unions, environmentalists and most Democrats oppose them — and, at least so far as fast-track goes, they’ve been joined on the “anti” side by tea party Republicans loath to give Obama any expansion of authority.

Trade is a major focus for Boustany, whose southwest Louisiana district includes ports along the Gulf of Mexico, and he is an enthusiastic supporter of Obama’s trade agenda.

“The world is not standing still,” he said in a House Ways & Means Committee hearing Thursday on the fast-track proposal. “Economic activity is going on at a furious pace in Asia and around the world. This activity is not waiting on the United States.”

The committee approved the proposal, setting up a vote on the House floor next month.

Fleming, who represents northwest Louisiana, seems unlikely to join Boustany in voting “yes” then.

“Before Congress grants any president additional authority, Congress should see evidence that the president is willing to respect the existing boundaries of the Constitution,” Fleming, who considers Obama’s 2014 executive orders on immigration as unconstitutional, wrote in an email earlier this year.

“Thus far,” Fleming wrote, “President Obama has trampled the rule of law and acted to sow distrust, not build trust.”

Fleming offered another argument this week against the Obama proposals. “We’re hearing something about some kind of an exchange, or utilizing foreign workers, and at a time when we have so many Americans not working, I think that’s a problem,” Fleming said, according to news accounts.

Fleming also reportedly warned that Obama “could open up trade with countries that are sworn enemies of ours. Before you know it, Iran could be one of our closest trading partners, and we’d be giving access to people who are sworn enemies.”

The idea that the Obama trade package is a Trojan horse for expanding immigration has been circulating among right-wing opponents of the proposal. In response, Ways and Means Committee Chairman Paul Ryan, R-Wis., denied any connection in a post on the committee’s blog.

Gregory Roberts’ email address is groberts@theadvocate.com.

and he is on Twitter, @GregRobertsDC. For more coverage of national government and politics, follow The Advocate Politics Blog at http://blogs.theadvocate.com/politicsblog.