WASHINGTON – For Mike Bloomberg, the one-way conversation with Democratic voters is about to end. By spending more than $400 million of his own money and largely bypassing his opponents by skipping the early primary states, Bloomberg has rocketed to double-digit support in enough national polls to qualify for Wednesday night’s Nevada debate. But as Bloomberg’s support has risen, so has the criticism from his Democratic foes as well as the broader scrutiny of his past comments and record as New York City mayor.