They didn’t work when Nixon and Kissinger tried it, even though the Soviet Union generally complied, because the revolutions that the USSR was fomenting continued to occur apace after the Soviets stopped fomenting in return for nuclear and economic concessions.

Treasury Secretary Jacob Lew warned ignoring recent steps by Beijing to liberalize its economy would endanger Chinese cooperation on other major geopolitical issues, particularly containing North Korea’s nuclear program.

They’re not working now with the People’s Republic of China, but for a different reason.

And

The departing Treasury secretary further warned against steps that would prompt China to withdraw its support for tougher sanctions against North Korea.

The PRC still isn’t taking steps to “liberalize its economy,” not when it’s actively interfering with its cross-border yuan flows, manipulating domestic interest rates with a view to control who gets to lend or borrow rather than an effort to maintain a stable monetary policy, manipulating its domestic stock markets as it did in 2015 and today with manipulating the legal environment, and on and on.

Nor has the PRC ever cooperated in any meaningful way with respect to sanctions connected to northern Korea’s nuclear weapons program.  The PRC routinely slow walks its agreement to sanctions (which is why their occasional prompt agreement is such news), and it ignores sanction violations as those occur across its border with northern Korea.

And—ignored by Lew—the PRC is accelerating its aggression in the East and South China Seas and increasing its pressures on the nations rimming the South China Sea to deal with them exclusively and one at a time on trade questions.

Before today’s linkages can have effect, the parties at both ends of the lever must be willing to be responsive.