To the list of political issues with which we began this mid-term election year, which had the Affordable Care Act and the economy at the top, we can now add Russia's involvement in Ukraine.

But while the domestic issues divide along fairly clear blue and red lines, the political question of what the U.S. should do about Russian President Vladimir Putin's deployment of the Russian military into Ukraine's Crimea is scrambling Washington's normal partisan lines.

For one, there's something of a Republican intra-party divide, as illustrated by two Republican senators thought to be interested in running for president in 2016 and one GOP congressman running for a Senate seat this year against a Democratic incumbent.

Sen. Marco Rubio, R-Fla., for instance, wants a robust anti-Russian response, including U.S. and other members of NATO extending economic and military assistance to Ukraine's transitional government. Rep. Tom Cotton, R-Ark, who hopes to defeat Democratic Sen. Mark Pryor, went even further than Rubio. He accused Obama of "trembling inaction" and likened Putin's move to Adolf Hitler's annexation of Austria or Anschluss and called for maximum economic pressure to be applied on Russia.

By contrast, Sen. Rand Paul, R-Ky, true to his libertarian, non-interventionist roots, warned U.S. policymakers even before Russia's involvement in Ukraine against upsetting the Russian bear. A he issued Friday reminded Russia of the negative economic consequences it would incur. Indeed, it read like something that could've been written by an officer on the State Department's Russia desk in its use of careful and non-threatening diplomatic language.

While the usually well-defined partisan split isn't there this time, there is still partisanship to be found. In the same vein as Cotton's Anschluss comment, conservatives have likened Obama to President Jimmy Carter during the 1979 Soviet invasion of Afghanistan, for instance. Sen. John McCain has called Obama "naive" about Putin.

That would be the same McCain, however, who joined a bipartisan group of Senate Foreign Relations Committee members that issued a letter of support for the Obama administration's efforts to raise economic pressure against Russia. The letter was clearly intended to strengthen the president's hand at a critical moment in his dealings with Putin.

In an interesting way, the international crises that have erupted on Obama's watch — Syria, Libya, Egypt among them — have tended to cause a diversion, if only temporarily from the unified messaging of both parties.

Politics may not stop at the waters edge (if it ever did), but it does get more complicated.

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