Trump fancies himself a great negotiator. Republicans are going to have to brush up on that, keeping in mind two principles. The first is that the real power in any relationship belongs to the party most willing to walk away from it. The second is that you always make sure you actually have what you want in hand before you hand over what you’re offering in trade. That second principle is going to be essential in dealing with Trump, who is not known for keeping his word or for even being embarrassed about breaking it, viewing honor as a poor negotiating tactic.

Trump wants an infrastructure-stimulus program. Congressional Republicans should get corporate tax reform and regulatory relief out of him before they write the check for that, which is going to be a big one. He wants immigration reform and cannot do it without Congress. Congressional Republicans should get, at the least, a brake on the growth of entitlement-benefit spending before they authorize breaking ground on any walls. Everyone wants Obamacare repealed; Republicans should make sure their alternative is signed into law with that repeal. If there is one thing about which Donald Trump has been consistent, it is that no one — not business partners, not wives, not political allies — can take him at his word.

Trump’s victory should be appreciated for what it is — but for no more than that. Republicans controlled Congress, the majority of governorships, and the majority of state legislatures before he came along. The nature of the presidency may make Trump the negotiating partner with the upper hand in many of these negotiations, but congressional Republicans keep the most important bargaining chip there is: The power to say no. They didn’t say no enough in the Bush years, but they got better at it during the Obama era. (Goodbye, Merrick Garland.) They should be ready to keep it up.

Just because we have one-party government doesn’t mean that everyone is on the same side.