NYT:

In 2009 and 2010 — the first Congress scrutinized by the Office of Congressional Ethics, which was created in 2008 — three lawmakers refused to cooperate with the office’s 68 investigations, a noncooperation rate of just 4 percent.

This year, six out of 14 House lawmakers under investigation have refused to participate — a rate of 43 percent, the highest on record.

Mr. Ashmawy said he believed the higher noncooperation rate was a result of investigators focusing on fewer cases, and more potentially serious ones. Lawmakers who may be glad to meet with ethics investigators to clear up an honest mistake or minor oversight are more reluctant to cooperate if they think they may face weightier consequences, he said.

There is no requirement that lawmakers cooperate with the Office of Congressional Ethics, but legislators who do so often are able to resolve what had appeared to be violations of ethics rules.

The fact that many will no longer even meet with ethics investigators reflects a troubling trend in American politics in which improper behavior is no longer a political liability, ethics experts say.