This particular button actually opens a popup, even though it is located on the same page.
![click here for image description][1]
I attempted to interact with the element using the following code:
driver.findElement(By.tagName("td")).findElement(By.id("leadCaptureList_leadCaptureList_assignCampaign")).click();
However, I encountered an error message stating "Unable to locate element: {"method":"id","selector":"leadCaptureList_leadCaptureList_assignCampaign"}"