It’s tough to be an executive nominee these days caught in the crosshairs of policy fights. Just ask Sarah Saldaña, who the Senate is likely to confirm Tuesday to head the Obama administration’s Office of Immigration and Customs Enforcement.

When first nominated, Saldaña was showered with accolades from fellow Texan Sen. John Cornyn (R). But now, just several months later, Cornyn doesn’t support her for the job.

Saldaña has learned a harsh reality in today’s Washington. If you support the president’s policies, you’ll run into trouble with Republicans on Capitol Hill. But if you don’t support them, it’s unlikely you’d get the nomination in the first place.

Cornyn spoke glowingly about Saldaña’s credentials at her September confirmation hearing, telling his peers that she has a “reputation for her decisive and fair temperament and her commitment to excellence.”

“If respect for the rule of law is our standard, and I think it should be, we would be hard-pressed to find a person more qualified to enforce the law than Ms. Saldaña,” he said then.

Ah, but that was then. On Tuesday morning on the Senate floor, Cornyn said he no longer supported her because she had defended President Obama’s executive action to delay deportations of some undocumented immigrants. (Cornyn also voted against her earlier this month when the Judiciary Committee narrowly approved her confirmation.)

Cornyn reiterated that he admired and respected Saldaña, “but if she is determined to help the president implement this deeply flawed executive action and refuse to enforce the law that Congress has written and has been signed by previous presidents, I can’t support her nomination,” he said.

In Washington, it’s impossible to please everyone all the time. Saldaña is expected to be confirmed Tuesday. And once she is, if she didn’t enforce Obama’s executive action, she’d suddenly be “spending more time with family.”