[@Sven the Silent]

No. No it wouldn't have ended Western Interventionism. It may have scaled it back to the point the Western authorities chose to deal with the Qing directly as opposed to the people as they did before. But the Boxer Rebellion didn't result in a total draw-back of Western Intervention. As a case: Russia refused to back out of Manchuria as spelled out in the Boxer Protocol after the rebellion was put down, effectively being a term to the Japanese-Russian war three-years later.

Any protocol put into place and recognition of the Qing Dynasty died when they did. The only lasting legacy of rejected or apprehensive western support may have been towards or from Northern China under Yuan Shikai whose politics were predominately defined by anti-Westernism akin to the Boxers. But the southern Republican half of China was willing to work with the west as well a anti-Qing and Monarchial, which Yuan Shikai was. Any western support that followed the Boxer Protocol in whatever symbolic manner they wanted would have been done directly to the Republican south or Sun Yet-Sen and his backers.