WASHINGTON – In the latest Senate flare up, Republicans are getting some help from Sen. Bob Casey (D., Pa.), reflecting how the ground has shifted under him since the GOP took over the Senate in January.

Three times this week, including once Wednesday, Casey has voted to advance a bill that has faced fierce Democratic opposition over language restricting federal spending on abortion.

Each time, he has been one of just four Democrats to back the bill while the rest of his party's senators oppose it in a procedural blockade that has stalled the measure. All of the Democratic supporters, like Casey, come from moderate to conservative states -- the others being from Indiana, North Dakota and West Virginia. The bill won 57 votes Wednesday, but needed 60 to overcome a Democratic filibuster threat.

For Casey, the votes are the latest example of how he has been pulled rightward on some key votes as Republicans set the agenda and pitch bills that appeal to the more conservative side of moderate states like Pennsylvania.

Casey was similarly one of few Senate Democrats who voted in favor of a bill authorizing the building of the Keystone XL pipeline. He also signed onto a bill backed largely by Republicans to impose conditional new sanctions on Iran, and he could soon be forced to weigh his support for that idea against his support for Obama, who has pleaded with Democrats to delay any votes while international negotiations with Iran are ongoing.

By contrast, when Democrats controlled the Senate and put forward politically popular ideas that tilted left, Casey's more liberal inclinations came out: he reversed previous stances and backed tougher gun laws and same-sex marriage, to choose two high-profile issues.

The latest debate on a Republican-crafted bill, though, has pulled into focus Casey's views on abortion, which are more conservative than most Democrats'.

The controversy stems from part of an otherwise non-controversial bill to help victims of sex-trafficking. The bill calls for creating a fund to help victims, using money from fines by people convicted of trafficking. The funds could not be used for abortion.

That language is similar to that in many federal spending bills, which routinely bar taxpayer money from being used to pay for abortions. Casey supports that language, even though Democrats have objected, worrying that a new precedent could be set, because this ban affects money coming from fines, not general tax revenue.

Most of the time, Casey is a reliable Obama supporter and holds to the Democratic party position. In many cases, he still does. Immediately after one trafficking vote he put out a statement of support for Attorney General nominee Loretta Lynch – who has been blocked by Republicans – and Wednesday he released a statement blasting the new GOP budget as "extreme" and "draconian."

But when it comes to some key votes, the playing field has been altered for the Pennsylvanian.

You can follow Tamari on Twitter or email him at jtamari@phillynews.com.