Last week, Marc Short, who had played a key role in the politically active billionaire Koch brothers’ organization Freedom Partners, moved to a senior role in Republican Sen. Marco Rubio’s presidential primary campaign. The New York Times reported that political advisers to the Koch brothers have been briefing people that Donald Trump is completely unacceptable as the GOP nominee. But behind the question of which candidate the Koch brothers prefer lies a more complicated story about the transformation of the Republican Party.

Alex Hertel-Fernandez, an incoming assistant professor of international and public affairs at Columbia University, and Theda Skocpol, the Victor S. Thomas professor of government and sociology at Harvard University, have been researching how Koch brothers-funded organizations have been changing the Republican Party in less immediately visible ways (here’s their paper). I interviewed them via email about their work (the interview has been lightly edited).

Henry Farrell: Political operatives connected to the Koch brothers and their political network keep popping up in the 2016 Republican presidential campaigns – like Corey Lewandowski, who heads Donald Trump’s campaign, and Marc Short from Freedom Partners, who just moved over to play a leading role in Marco Rubio’s campaign. Your research argues that today’s Koch network is a much bigger player in conservative and Republican Party politics than other well-known groups pushing conservative economic policies, such as the Club for Growth and Americans for Tax Reform (ATR). What is new here?

Hertel-Fernandez and Skocpol: You are right that Koch-connected operatives and alumni of Koch political organizations are ubiquitous in today’s Republican politics – not just in campaigns, even campaigns fighting one another as the Trump and Rubio campaigns are currently doing, but also sprinkled through GOP legislative and executive staff offices in Washington, D.C., and dozens of state capitols.

Simply put, the Koch network is a GOP-aligned political effort like nothing we have seen, including operations such as the Club for Growth and Americans for Tax Reform that also aspire to sharply reduce taxes, government spending and regulations. Compared to those groups, the Koch network now operates on a much vaster scale and is able to penetrate and reshape much of what Republicans do in elections and government.

Some background on the evolution of the Koch network can help make the point. Of course, multibillionaire industrialists Charles and David Koch have worked for decades to change American politics. Starting in the 1970s and 1980s, they launched think tanks and university centers to promote libertarian ideas; then they moved in the 1980s and 1990s to support advocacy groups fighting taxes and government regulations. A yet more ambitious phase started in the mid-2000s, when the brothers and a few associates launched Americans for Prosperity (AFP) as a centrally directed but federated organization with paid staffers in the states who can deploy resources and mobilize millions of activists on contact lists. Recently, the overarching Koch operation has added specialized organizations meant to collect and analyze voter data and do outreach to Latinos, youth and military veterans. Today’s Koch network performs a full array of political party-like activities – and it is funded not just by the brothers themselves but by hundreds of wealthy conservatives who meet at twice-yearly seminars and channel dues and generous donations through the Freedom Partners Chamber of Commerce directly into the coffers of AFP and the other Koch-run political organizations.

As a result of this latest evolution, the Koch network has more capabilities than ATR and the Club for Growth to combine lobbying with activist mobilization and electioneering. In addition, Koch donors gave close to $400 million leading into 2012 and have pledged to spend between $700 million and $900 million for the 2015-16 cycle. By comparison, the Club for Growth spent about $22 million in disclosed federal contributions for the 2012 election and ATR spent about $16 million. Even if these estimates of spending orchestrated by the Club and ATR are low, the Koch network is clearly able to deploy resources on a vastly greater scale, much closer to the combined budgets of all of the Republican Party’s national election committees.

HF – You argue that Americans for Prosperity is the most important and unusual organization in the current Koch network. Why?

AH-F & TS – AFP combines features we do not usually see together in U.S. politics. It is centrally run like a private corporation, but also federated like U.S. government and political parties. In addition to a national office and regional managers, AFP has state offices with paid directors and other staffers who operate in regular contact with citizen activists. Before Barack Obama moved into the White House, AFP already had 58 managers and operatives, including paid directors permanently installed in 15 states across all regions, encompassing close to half of the U.S. population (and their representatives in Congress). By now, AFP is similarly organized in 34 states covering 80 percent of the population. This is a vast operation that can direct resources in both election efforts and legislative campaigns. And AFP operates in close cooperation with other state-based conservative networks such as the American Legislative Exchange Council and the State Policy Network linking free-market think tanks in all 50 states.

HF – What difference has all of this Koch network activity made for the Republican Party?

AH-F & TS – The Koch network has helped to move the GOP far to the right on the full array of economically relevant issues – perpetuating during the 2000s the process of asymmetric rightward political polarization that started several decades ago. The network has such vast resources and presence that it has been able to draw GOP candidates and officeholders into alignment with its policy agenda, moving seamlessly from helping to elect very conservative Republicans to lobbying them once in office to effectuate preferred policies. Koch influenced Republicans have worked to block Medicaid expansion in the states, weaken public sector labor unions, stop environmental and climate change reforms, and limit government spending. Many of these Koch preferred policy stands are at odds with what most voters, even many GOP voters, want from government. In addition, the Koch network has sparked intra-GOP fights about subsidies for private firms and infrastructure development. These fights can pit AFP against business associations like the U.S. Chamber of Commerce and state Chambers, creating cross-pressures on GOP legislators. We know that the Koch network has real clout, because it has persuaded Republicans to move further toward the ultra-free-market right than most voters and even many business groups want to go.

To us, it has been fascinating to discover that, unlike most policy advocacy groups, the Koch network does not just stand apart and push from the outside. We have done detailed research on the careers of AFP state directors before and after their time with that organization. Of the 58 directors who served in the 15 enduring state organizations established by 2007, nearly seven in 10 had previously worked on GOP legislative or executive staffs or on Republican election campaigns, and nearly three in 10 would later hold important GOP posts after working for AFP. Many other AFP veterans owned or managed GOP-linked consulting businesses. Although we have more research to do, we find so far that ATR and the Club for Growth recruit professional staffers primarily from other conservative advocacy organizations. AFP is much more tightly intertwined with the Republican Party.

Nor is the Koch network some sort of third party, as some commentators have implied. Even though the Koch network now deploys funding and staffing on a scale close to the entire Republican Party, it is not a separate entity. The Koch brothers and their allies have made a very deliberate decision to work through the Republican Party at all levels and pull its agenda to the right. As political scientists, we understand why this makes sense. Parties carry important brand names familiar to voters and perform crucial coordinating functions in Congress and state legislatures. To use a biological analogy, the relationship between the Koch network and the GOP is best understood as similar to a parasite and its host. Parasites need hosts to survive and grow – and in a similar way Koch-orchestrated conservatives need the Republican Party to win elections and influence governing decisions.

We have every reason to think that Koch influences will continue to pervade Republican politics – even if particular candidates (such as Donald Trump) not preferred by the brothers and many of their donors defeat other candidates (such as Marco Rubio or Ted Cruz) that the Koch network would find more simpatico. After all, right now we find Koch-connected donors and operatives playing major roles in all of these GOP presidential campaigns; and if any of these men ends up moving into the White House in 2017, he will surely tap Koch operatives and ideas to govern. That includes Donald Trump, because we know that his campaign manager, the former highly successful head of Americans for Prosperity in New Hampshire, has already recruited other Koch alumni and would be able to attract many more.

Indeed, even if a Democrat wins the 2016 presidential election, she will find herself dealing with key network-supported Republicans in Congress, above all House Speaker Paul Ryan, who is prepared to push forward a budget and other policy initiatives long favored by the Koch network. Democrats will also face opposition from AFP and its allies in most state governments. Regardless of which candidates win in November, the Koch network has succeeded in shifting the center of gravity in 21st-century U.S. politics.

Alex Hertel-Fernandez is a Ph.D. student at Harvard and an incoming assistant professor of international and public affairs at Columbia University.

Theda Skocpol is the Victor S. Thomas professor of government and sociology at Harvard University and director of the Scholars Strategy Network.